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The organic linkers' functional groups highly impact the properties of MOFs' morphology, structure, physical, electrochemical properties and their performance as supercapacitor electrode materials. [Display omitted] • The first exploration of effects of functional group in organic linkers on properties of four MOF electrodes and their performance in supercapacitors. • Electrodes with –OH, –NH and −SH groups have very low charge transfer (< 1 Ω). • NiCo-H electrode has a high specific capacitance of 1495 F g−1 of due to its large specific surface area of 980 m2 g−1. • NiCo-SH electrode has a high normalized areal specific capacitance of 26 F m−2 as well as stable cycling performance of 80 % retention after 10,000 cycles. The history of developing supercapacitors with increased performance is inextricably linked to the exploration and design of suitable electrode materials. Metal-organic frameworks (MOFs) have attracted intensive attention for use in high-performance supercapacitors thanks to their large specific surface area, tuneable pore sizes and crystal structure. Understanding the influence of MOF structures and properties on the performance of supercapacitors is critical to enhancing their performance. However, so far researchers have been keen on exploring metal atoms in MOFs and have ignored the effects of organic ligands, especially the functional groups thereon, on supercapacitors. In this work, we have studied the impact of organic linkers' functional groups on the properties of MOFs and how this influences their performance as supercapacitor electrode materials. We synthesized four MOFs with different functional groups, including hydroxyl, nitride and thiol groups and characterised their physicochemical properties and their performance as supercapacitor electrode materials. Characterisation of the specific surface area shows that the BET area decreases from 980.3 m2 g−1 for the original MOF to 12.2 m2 g−1 when the thiol group is incorporated. Furthermore the –OH, –NH, and −SH functionalities reduced the charge transfer resistance (< 1 Ω) and induced more pseudocapacitance, whereas the –OH group dramatically increased the hydrophilicity of the electrode and rate performance of supercapacitors. Although the MOFs without extra function group showed the highest specific capacitance of 1495F g−1, analysis of the normalized areal specific capacitance only shows 1.5 F m−2. The MOFs with the −SH group showed the highest normalized areal specific capacitance of 26F m−2 as well as stable cycling performance of 80 % retention after 10,000 cycles. [ABSTRACT FROM AUTHOR]

• The paper reviews breakthroughs in ASSLBs, focusing on new solid electrolytes and advanced electrodes for better performance. • The study identifies key obstacles in SEs, including ion transfer limits, interfacial resistance, and stability issues. • The paper evaluates the potential for large-scale production of ASSLBs for commercial applications. All-solid-state lithium batteries, which utilize solid electrolytes, are regarded as the next generation of energy storage devices. Recent breakthroughs in this type of rechargeable battery have significantly accelerated their path towards becoming commercially viable. Nevertheless, the development of such devices is impeded by various obstacles, including limitations in ion transfer capability, interfacial hurdles, and chemical and electrochemical stability. This paper provides a comprehensive review of the latest advancements in all-solid-state lithium-based batteries. The main emphasis is on the fabrication techniques, novel solid electrolytes, and the application of advanced cathode and anode materials to expedite research and development in this field. Moreover, the feasibility of large-scale manufacturing of solid-state batteries has been evaluated. Finally, the most practical and effective approaches for the advancement of these batteries have been proposed and examined. [ABSTRACT FROM AUTHOR]

• MXenes are 2D materials that are significantly impeded by layer sticking, which prevents them from realizing their full potential. • Here, we present a new, simple approach to separate stuck MXene layers (exfoliate) by using a laser. • The laser locally heats the MXene and causes rapid extraction of water between the layers. • The exfoliated MXene demonstrates excellent performance as supercapacitor electrodes. MXenes-based compounds, particularly Ti 3 C 2 T x, have been studied intensively as electrodes for supercapacitors due to their layered structure and high conductivity, enabling facile ion diffusion and charge transfer. However, tight restacking of the 2D layers in these materials limits their practical, accessible surface area, thereby impeding their capacity and rate capability performance. To mitigate this phenomenon, we present a new approach using a processing method based on laser beam irradiation to modify Ti 3 C 2 T x films. We found that the laser treatment induces chemical and morphological changes, ultimately optimizing the stacking arrangement of the MXene electrodes and consequently enhancing their capacity in both neutral and acidic electrolytes. Furthermore, the laser-modified MXene electrodes demonstrate excellent rate capabilities, showing 84 % retention at extreme rates of 0.5 V compared to only 33 % of the original Ti 3 C 2 T x electrodes. Finally, we discuss the chemical and physical changes induced by the laser treatments and their influence on the electrochemical behavior of the lasered MXene. The principles of laser exfoliation discovered in this study can be implemented in broader 2D materials for various applications. [ABSTRACT FROM AUTHOR]

The excellent ammonium removal performance of the P/M-C-50 electrode was mainly attributed to the synergistic effect of the increased layer spacing and the introduced oxygen vacancy after PANI intercalating and the 1D/2D conductive interconnect structure constructed by CNTs. The structural characterization and DFT studies reveal that P/M-C-50 has high conductivity, remarkable structural stability, low energy barrier for NH 4 + ions diffusion, and has broad potential as a CDI ammonium removal electrode. [Display omitted] • Chemical traction and pre-intercalation strategies can optimize the MnO 2 structure. • The introduced oxygen vacancy is conducive to the adsorption and diffusion of NH 4 +. • The introduction of CNTs enhanced the conductivity and stability of P/M-C-50. • High SAC of 160.0 mg g−1 and fast SAR of 1.07 mg g−1 s−1 were achieved. • DFT revealed the storage mechanism and strengthening mechanism of NH 4 +. The δ-MnO 2 exhibits an ideal capacitive deionization (CDI) electrode for the efficient removal of ammonium ions (NH 4 +), owing to its unique layered structure that facilitates effective insertion and extraction of ions. However, MnO 2 is constrained by self-aggregation, inadequate electrical conductivity, and sluggish reaction kinetics in practical applications, leading to subpar ammonium removal performance. Here, the polyaniline (PANI) intercalated MnO 2 and carbon nanotubes (CNTs) composites (P/M-C-X) were synthesized by a straightforward and swift one-step inorganic/organic interface reaction using the chemical traction effect of aniline. The synergistic effect of the increased layer spacing and the introduced oxygen vacancy after PANI intercalated and the 1D/2D conductive interconnect structure constructed by CNTs can effectively improve the electrical conductivity, promote ions/electrons diffusion, and enhance the charge reaction kinetics. As results, P/M-C-50 exhibits excellent NH 4 + removal performance, including the maximum salt adsorption capacity (SAC) (160.0 mg g−1), ultra-high salt adsorption rate (SAR) (1.07 mg g−1 s−1), and good cyclic stability. Furthermore, the comprehension of NH 4 + storage mechanism has been enhanced through structural characterization, electrochemical analysis, and theoretical calculation. This study shows that P/M-C-50 has broad potential as a CDI ammonium removal electrode, and lays a solid foundation for the effective recovery and reuse of ammonium resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molecularly designed SOFPB incorporates the merits of various functional groups. • SOFPB endows NCM622 or graphite electrode with wide-temperature performance. • NCM622/graphite full-cells with SOFPB stably cycle over -10 °C to 55 °C. High-voltage nickel-rich/graphite full-cells offer significant potential for enhancing the energy density of lithium-ion batteries (LIBs), yet rapid capacity degradation at extreme temperatures remains a critical challenge. We introduce a novel electrolyte additive, 5-(t-butyldimethylsilyloxy)-2-fluorophenylboronic acid pinacol ester (SOFPB), which incorporates multifunctional boron, phenyl-, fluorine, and siloxy groups to tackle this issue. In Li/NCM622 half-cells, 0.3 wt% SOFPB achieves a capacity retention 2.6 times that of the Baseline after 400 cycles at -30 °C, and maintains 78.4% and 77.5% capacity after 300 cycles at 25 °C and 55 °C, respectively, compared to 63.4% and 3.8% for the Baseline. This improvement is attributed to a robust cathode electrolyte interphase (CEI) with high lithium-ion conductivity and oxidative stability. Li/graphite half-cells with SOFPB show rapid capacity recovery at 0 °C and retain 99.6% and 72.4% capacity after 500 and 150 cycles at 25 °C and 55 °C, respectively, compared to 60.3% for the Baseline at 25 °C. This performance is due to a flexible solid electrolyte interphase (SEI) that improves lithium-ion diffusion. Furthermore, NCM622/graphite full-cells highlight the practical value of SOFPB, with retention of 91.6%/77.7%/97.7% after 200/150/50 cycles at 25 °C/-10 °C/55 °C, respectively, compared to 52.9%/25.2%/43.9% for the Baseline. The multifunctional design of SOFPB provides valuable insights for developing advanced electrolyte additives for high-voltage LIBs with broad climate adaptability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designed a highly efficient and low-consumption two-stage continuous effluent reactor. • TiO 2 NAs capture protons to synergistically enhance catalytic activity with MXene's facilitated proton reduction. • Degradation of tigecycline reached 86.66 % in only 20 min. • Electrode performance unaffected by prolonged air exposure and repeated use. In this study, a composite electrode (MXene/TiO 2 NAs@CC) based on TiO 2 nanotube arrays (NAs) and two-dimensional MXene-coated carbon cloth (CC) was prepared. The electrode greatly improved the catalytic activity by capturing protons through the abundant active sites of TiO 2 nanotube arrays and promoting proton reduction with the high conductivity of MXene. Moreover, the composite electrode possessed the largest specific surface area (9.1660 m2·g−1) according to the results of the BET test. Under optimal conditions, the composite electrode degraded tigecycline (TGC) up to 86.66 % in 20 min. Furthermore, the electrocatalytic performance was not affected after 10 cycling experiments and 60 days of exposure to air, indicating its excellent stability. In addition, the cathodic co-catalytic reaction mechanism involving anode ·OH, HClO, and cathode H* was proposed. The degradation pathways of TGC and the toxicity of possible intermediates were also analyzed. Finally, a two-stage continuous wastewater reactor with high efficiency and low consumption (90.46 % removal rate, 0.061 kWh/m3) was designed. This study provides a new idea for designing an electrocatalytic reactor with high efficiency, stability, and low consumption, enriching the field of electrocatalytic treatment strategies for antibiotic wastewater. It is of great significance for the protection of the water environment and human health. [ABSTRACT FROM AUTHOR]

[Display omitted] • Derivation of a new performance factor based on mass transfer and pumping power. • Agreement between experimental and simulated data for pillar array electrodes. • Pillar diameter and interpillar distance determine the performance of the arrays. • Hydrodynamic resistance and dimensionless numbers determine the flow regime. • Performance factor permits to compare pillar arrays and reported porous electrodes. This work introduces and validates a Hydrodynamic Electrode Performance Factor (HEPF) for flow reactors. Traditional approaches to electrode optimization often rely on separated mass transfer and pressure drop metrics, hindering comparisons. We address this issue by combining electrochemical and hydrodynamic parameters through a new mathematical expression. This formulation draws inspiration from established equations in heat transfer and the widely recognized Chilton-Colburn analogy, aiming to develop a quantification method independent of the experimental arrangement. The HEPF is complementary to the well-established volumetric mass transfer coefficient and to Storck's energetic effectiveness postulates for electrochemical reactors. Additionally, this study validates the proposed equation experimentally and then applies it to evaluate pillar array electrodes using 2D computational fluid dynamics simulations for laminar flow conditions. Both experimental and simulation approaches are used to analyze the hydrodynamic behaviour of the electrodes, utilizing the Forchheimer and Hagen-Poiseuille numbers. Notably, preliminary turbulence effects are observed at Reynolds numbers as low as 50 to 125. Visualization of velocity streamlines revealed distinct wake formation behind the pillars at these low Reynolds numbers. This study also explores how reactor inlets, outlets, and tubing pressure losses affect electrode performance. Results emphasize the importance of considering pressure drop, which is integral to the new hydrodynamic performance factor. Analysis of pillar array electrodes demonstrates that reducing both interpillar distance and pillar radius leads to improved electrochemical performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A 3D conductive network skeleton is developed by SWCNT-COOH and PVA-PAA to buffer the dramatic volume expansion of Si. • The skeleton has high electrical conductivity and mechanical strength. • The flexible anode based on 3D conductive network skeleton has obviously enhanced cycle stability. • The full cell based on 3D conductive network skeleton can power a red LED strip under various bending, meeting the need of broad applications in flexible electronic devices. Silicon anode undergoes dramatic volume expansion during charge and discharge, causing structural and interfacial instability that severely degrades battery cycling performance. Herein, we propose a three-dimensional (3D) flexible self-standing SiMP/SWCNT-COOH@PVA/PAA anode, in which carboxylation-modified single-walled carbon nanotubes (SWCNT-COOH) construct a highly conductive and flexible skeleton to provide rapid electron transport channels for micron silicon (SiMP), while polyacrylic acid-polyvinyl alcohol (PVA-PAA) cross-linking layer forms a high-strength polymer interface to strengthen the conductive skeleton and helps to maintain the structural integrity of SiMP. The resulting electrode exhibits ultra-high electrical conductance (12406 S m−1) and exceptional mechanical characteristic (tensile strength of 46.95 MPa). More importantly, it demonstrates extremely stable electrochemical properties, with an impressive maximum capacity of approximately 2868.5 mAh g−1 at 0.2C, while retaining an exceptional 96.49 % of capacity even after 100 cycles. A consistent capacity of 1000 mAh g−1 at 1C throughout 1000 cycles is also realized. Furthermore, a flexible full battery based on SiMP/SWCNT-COOH@PVA/PAA anode achieves a discharge capacity of 49.5 mAh g−1 following 100 cycles, and illuminates a LED strip normally under various bending conditions. These results are expected to open a new way towards enhanced performance silicon-based electrodes within flexible LIBs. [ABSTRACT FROM AUTHOR]

• A Mo 3 C 2 /laser-induced graphene (LIG) was synthesized via one-step CO 2 laser induced conversion process. • Self-assembly enables the macroscopic arrangement of the lamellar hydrogel/metal-ion matrix into hierarchical porous structure. • Mo 3 C 2 /LIG enhances both mechanical and electrical properties. Transition metal carbides (TMCs) have garnered significant attention in various energy applications owing to their outstanding conductive and electrochemical properties. Despite these advantages, challenges persist in terms of non-toxicity and efficient fabrication methods. In this study, a Mo 3 C 2 /laser-induced graphene (LIG) heterostructure was synthesized via one-step CO 2 laser induced conversion process. The specific area capacitance of the Mo 3 C 2 /LIG hybrid electrode reached 23.5 mF cm−2, which is 2.5 times higher than that of pure Mo 3 C 2 and 9 times greater than pure LIG electrodes. Moreover, the hybrid electrode exhibited robust cycling stability, maintaining 98.4 % of its initial capacitance after 10,000 charge–discharge cycles. Theoretical simulation also revealed superior hydrogen adsorption and high electrical conductivity of the Mo 3 C 2 /LIG hybrid electrode. This work presents a promising approach for developing advanced molybdenum carbide-based composites and offers an alternative strategy for enhancing the electrochemical performance of capacitive electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • CC substrate was etched by Co 3 O 4 under high temperature to form mesoporous structure. • The loaded Co 3 O 4 was completely transformed in to Co 1-x S after two sulfurization processes. • TAA-derived NSC coated the Co 1-x S and prevent their slipping, dissolution and agglomeration. • The formed hierarchical pores could accommodate more Co 1-x S and thus enhance the pseudo-capacitive behavior. • The p-CC/Co 1-x S/NSC-2 electrode exhibits high flexibility and capacitive properties. The capacitive performances of flexible electrodes highly depend on their architectures and redox activity. In this work, Co 1-x S/N, S-codoped carbon (NSC) loaded porous carbon cloth (p-CC) was prepared through an etching procedure and a followed repeated-sulfurization process. Since the porous CC could accommodate more Co 1-x S nanoparticles and the phase structure of Co 1-x S was well controlled by the repeated-sulfurization process, the obtained p-CC/Co 1-x S/NSC electrode with optimized composition and architecture exhibits high areal capacitances of 1263.8 mF cm−2 at 1 mA cm−2 and 858.6 mF cm−2 at 50 mA cm−2. The deposited NSC on Co 1-x S could effectively prevent their slipping and agglomeration, and thus make the electrode exhibit high capacitance retention of 99.7 % after 20,000 charge–discharge tests. The all-solid-state symmetric supercapacitor assembled by the formed electrodes and ionic liquid/gel electrolyte shows a maximum energy density of 1.34 mWh cm−3 at the power density of 9.55 mW cm−3. These results present a new strategy for the construction of cobalt-sulfide/carbon based flexible electrode with high capacitive performances. [ABSTRACT FROM AUTHOR]

A multilayer arrangement configuration was evaluated for low-loading bifunctional oxygen electrodes (BOEs) for PEM unitized regenerative fuel cells (URFCs). The Pt to IrO x ratio was studied in two distinct multilayer catalyst-coated membrane configurations, i.e., with the IrO x layer near the GDL or the PEM. A novel approach to fabricate the Pt black catalyst layer (CL) was used with a Pt nanoparticle ink printed first and then impregnated with ionomer by inkjet printing a Nafion dispersion. The electrodes were characterized via scanning electrode microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The results show that the performance of the multilayer electrodes is highly dependent on the position of the CLs in the electrode and that the Pt to IrO x ratio is critical for the successful operation of the electrode when the Pt layer is in contact with the PEM. At high catalyst loadings, the poorly conductive IrOx layer, in contact with the GDL, acted as a barrier for the electrons to reach the Pt layer, increasing the high-frequency impedance of the cell and leading to a second semicircle. The catalyst ratio study showed that, at lower IrOx loadings, the multilayer approach outperforms the mixed catalyst BOEs when the Pt CL is in contact with the PEM reaching a round-trip (RT) efficiency of 51.2% at 500 mA/cm2 and 43.8% at 1000 mA/cm2 with a catalyst loading of only 0.56 mg/cm2 and a 9:1 Pt:IrO x ratio. Once the CLs position and the catalyst ratio are optimized, the electrodes fabricated in this work achieved the highest RT efficiency for a multilayer arrangement and one of the highest by the amount of catalysts of any constant gas BOE reported in the literature. • Low-loading bifunctional electrodes with a multilayer arrangement by inkjet printing. • Extra impedance due to charge transfer in the IrOx layer when on top of the Pt layer. • Comparable performance to mixed catalyst electrodes once catalyst ratio is optimized. • Round-trip efficiency of 51% at 0.5 A/cm2 with less than 0.7 mg/cm2catalyst. [ABSTRACT FROM AUTHOR]

Enhanced wastewater treatment and electricity generation through capacitive microbial fuel cells utilizing nitrogen-doped NiO/CNF-decorated micro-carbon beads in fixed packed bed electrodes. [Display omitted] • Capacitive NiO-N-CNF/ACB electrodes excels in MFCs, boosting performance. • High surface area of CNF aids efficient wastewater contact and biofilm development. • Effective energy storage with excellent capacitance of 754 F/g and cumulative total charge of 255 C/g. • 74 % COD reduction shows NiO-N-CNF/ACB's superior efficacy over ACB (50 %) in wastewater treatment. • Microbial diversity also enhances MFC efficiency in power generation and COD reduction. Nitrogen-doped nickel oxide-catalyzed carbon nanofiber-decorated micro-activated carbon beads (NiO-N-CNF/ACB) were synthesized through suspension polymerization and employed as capacitive fixed-packed bed electrodes in microbial fuel cell (MFC-) for wastewater treatment and byproduct electricity generation. The capacitive electrode was meticulously designed to manifest enhanced characteristics crucial for MFC applications. The large specific surface area of NiO-N-CNF/ACB offers advantages in terms of catalytic sites and stored charge produced by electrogenic bacteria to form an electrochemical double-layer on the electrode, thereby enhancing power generation. The incorporation of NiO, coupled with graphitic contents, biocompatibility, and the formation of three-dimensional structures, contributes to the excellent performance of the NiO-N-CNF/ACB electrodes. The NiO-N-CNF/ACB electrodes-based MFC operated in batch mode demonstrated an open-circuit potential of 0.8 V, an impressive maximum power density of 2900 mW/m3, and a noteworthy 74 % reduction in chemical oxygen demand. Additionally, the synthesized NiO-N-CNF/ACB exhibited a remarkable specific capacitance 754 F/g and a cumulative total charge of 255 C/g, surpassing the corresponding values for plain NiO-ACB and ACB. This study positions NiO-N-CNF/ACB as a promising capacitive packed bed electrode material, offering enhanced power generation, efficient wastewater treatment, and superior biofilm formation, thereby advancing the potential for sustainable and efficient MFC systems. [ABSTRACT FROM AUTHOR]

• ZIF-67/phosphorus-doped carbon nanofiber (ZIF-67@PCNFs) hybrid materials are developed for supercapacitor electrodes. • P-doping lignin-based carbon nanofibers and the unique properties of ZIF-67 after calcination enhance electrode flexibility and boost energy storage. • ZIF-67@PCNFs40-300C calcinated at 300 °C showed the highest specific capacitance (307.7 F/g at 0.1 A/g) with 99.9 % retention after 5,000 cycles. In this work, phosphoric acid is utilized as a precursor to improve electrospinnability of lignin/polyvinylpyrrolidone (lignin/PVP) solution as well as flexibility and uniformity of the resulting lignin-based carbon nanofibers. By treating with phosphoric acid, the carbon nanofibers obtained are doped with phosphorus, resulting in improved surface wettability and electrochemical properties. In the range of 0–60 wt% H 3 PO 4 , phosphorus-doped (P-doped) carbon nanofibers prepared from 40 wt% H 3 PO 4 (PCNFs40), as electrode materials, show the highest specific capacitance of 153.9 F/g at a current density of 0.1 A/g. To enhance electrochemical performance of the P-doped carbon electrodes, we further develop zeolite imidazole framework-67 (ZIF-67)/P-doped carbon nanofiber hybrid materials (ZIF-67@PCNFs40) by simple deposition of ZIF-67 on PCNFs40 at ambient temperature. After calcination at 300–400 °C in air, ZIF-67 on ZIF-67@PCNFs40-300C and ZIF-67@PCNFs40-400C is transformed into cobalt oxide. Due to their high specific surface area (507.3 m2/g) and abundance of active surface elements, ZIF-67@PCNFs40-300C exhibit high specific capacitance (307.7 F/g at a current density of 0.1 A/g in a 2.0 M H 2 SO 4 electrolyte) with excellent cycling stability (99.9 % capacitance retention after 5,000 cycles). The ZIF-67@PCNFs40-300C show a great potential as flexible and binder-free hybrid electrodes for high performance supercapacitor with an energy density as high as 42.7 Wh/kg at a power density of 270 W/kg. [ABSTRACT FROM AUTHOR]

[Display omitted] • MWCNT@MFe 2 O 4 (M=Fe, Mn) nanocomposite have been prepared and introduced into paper based electrodes. • The asymmetric interdigital patterns of nanopaper electrodes with excellent electrochemical performance are developed. • The optimized FASCs present an excellent electric performance (309.8 mF cm−2 and 110.2 μW h cm−2). • An energy density of 273.8 μW h cm−2 at 0.47 mW cm−2 power density was achieved by a stacked interdigital FASCs. Flexible asymmetric supercapacitors (FASCs) are potential energy storage devices for wearable electronics, considering that these have a wide operating voltage window, high specific capacity, and high energy density. However, achieving high energy density through the optimization of structure and electrode remains a challenge. Herein, two electrode inks with exceptional homogeneity nature and stability are prepared by using in-situ grown Fe-based spinel oxide (MFe 2 O 4 = Fe 3 O 4 /MnFe 2 O 4) on multi-walled carbon nanotubes (MWCNT) combined with eco-friendly and renewable cellulose nanofiber (CNF). Meanwhile, ultrathin flexible asymmetric interdigital nanopaper electrodes (NFT@MnFe and NFT@Fe) with customized patterns are fabricated through a one-step mask-assisted vacuum filtration strategy by using the obtained electrode inks. The planar interdigital FASC device based on the NFT@MnFe cathode and the NFT@Fe anode has excellent area specific capacity (309.8 mF cm−2), energy density (110.2 μW h cm−2), and power density (0.47 mW cm−2). The FASC maintain over 95 % of the original capacity after 5000 charge/discharge cycles. Noteworthy, a stacked interdigital FASC can be achieved with an energy density of up to 273.8 μW h cm−2 at 0.47 mW cm−2 power density, combining the structural benefits of planar interdigital and sandwich-type devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrathin Pt overlayer was fabricated on Ni substrate using an SED method. • Pt loading mass was precisely controlled at a microgram scale. • Electron-deficient Ni improved *OH adsorption, allowing NH 3 adsorption on Pt site. • Acid etching provided simple surface engineering method for Pt facet control. • E-HNO 3 -Pt5/Ni with high Pt(1 0 0) ratio showed high catalytic activity for AOR. Utilizing ammonia for hydrogen production via ammonia oxidation reaction (AOR) remains a challenge owing to insufficient electrode performance and high cost of noble metal. Herein, we performed repeated self-terminated electrodeposition (SED) of Pt on Ni substrate to obtain Pt/Ni electrodes. The electron-deficient Ni sites prefer *OH adsorption and serve as a reservoir for NH 3 dehydrogenation, thereby promoting NH 3 adsorption on Pt sites. Additionally, this iterative process enabled precise regulation of the Pt loading mass. Pt5/Ni electrode exhibited the highest catalytic activity for AOR. Subsequently, immersing this electrode in various acid solutions resulted in surface morphologies with numerous well-defined pits, driven by the adsorption of different electrolyte ions. Specifically, etching in HNO 3 led to a higher Pt(1 0 0) density, further enhancing the electrode's catalytic performance for AOR. Thus, this study offers a simple, fast, and spontaneous method for facet engineering ultrathin Pt overlayers on Ni substrate under ambient conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A V-doped Ni(OH) 2 electrode is proposed for cathode for ASCs. • The OER during CV activation greatly enhances the electrochemical performance. • The V doping facilitates the OER during CV activation. • The electrochemical activation mechanism is elucidated. Large capacitance and stable cycling performance of electrodes are critical for the success of aqueous asymmetric supercapacitors. In this study, we propose a novel synergistic strategy involving V doping and electrochemical activation to optimize the electrochemical performance of Ni(OH) 2. Our results demonstrate that the oxygen evolution reaction (OER), occurring during the activation process, is crucial for performance enhancement, with V doping significantly facilitating this reaction. The optimized V-Ni(OH) 2 -A 0 electrode exhibits a high specific capacitance of 3.9 F cm−2 at 10 mA cm−2 and excellent long-term cycling stability, retaining 88 % of its initial capacitance after 10,000 cycles at a current density of 30 mA cm−2. Furthermore, the aqueous asymmetric supercapacitor, consisting of V-Ni(OH) 2 -A 0 and carbon cloth, achieves an energy density of 0.50 mWh cm−2 with a power density of 10.92 mW cm−2, with exceptional cyclic performance, maintaining 96 % of its capacitance after 30,000 cycles at a current density of 25 mA cm−2. These findings underscore the potential of leveraging the OER to significantly enhance the electrochemical performance of Ni(OH) 2 based electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The pore microstructure and surface-interface coupled to mediate the morphology-performance relationship. • Quantitatively analyzed the driven effect of the pore size and micromorphology on EDL progress. • Elucidated the ions storage behaviors mediated by surface-interface characteristics. • Electrodes with high-energy crystal facets and 3D porous structure performed good cycling stability. Manganese dioxide (MnO 2) materials are one of promising cathode candidates for capacitive deionization (CDI) applications, with their morphology significantly impacting the performance of the electrode material itself. Therefore, this study systematically investigates the structure-performance relationships and the micro-interface ion storage mechanisms of four morphologies of MnO 2 (1D nanorods (NNMO), nanowires (NWMO), 3D microspheres (MMO), and hollow urchin-like spheres (HUMO)) in relation to their capacitive deionization performance with typical heavy metal ions (Cd2+) through experimental and theoretical calculations. In terms of pore morphology, capacitance significantly increases with increasing surface curvature of materials, demonstrating a clear pore structure-dependent characteristic. NNMO, with the smallest pore size, has much lower surface capacitance (∼0.15 μF cm−2) than other materials (∼0.33 μF cm−2). As pore size increases, the capacitance distribution difference driven by pore structure size gradually disappears. Regarding surface and interface characteristics, high-energy crystal facets facilitate electron transfer ({310}>{200}≈{211}>{100}) and increase the proportion of surface active sites (O sur), thus promoting CDI absorption kinetics. During the capacitive deionization process, the pore structure (∼77 %) and surface-interface characteristics (∼23 %) exhibit highly coupled features and the driving force for interfacial ion storage among the four materials is in the order of HUMO>MMO>NWMO>NNMO. This work elucidates the morphology-dependent capacitive processes of MnO 2 nanomaterials, enhancing the understanding of structure- electrochemical process at the nanoscale but also providing effective guidance for the design and development of practical, high-performance CDI electrode materials. [ABSTRACT FROM AUTHOR]

• ZIF-67/phosphorus-doped carbon nanofiber (ZIF-67@PCNFs) hybrid materials are developed for supercapacitor electrodes. • P-doping lignin-based carbon nanofibers and the unique properties of ZIF-67 after calcination enhance electrode flexibility and boost energy storage. • ZIF-67@PCNFs40-300C calcinated at 300 °C showed the highest specific capacitance (307.7 F/g at 0.1 A/g) with 99.9 % retention after 5,000 cycles. In this work, phosphoric acid is utilized as a precursor to improve electrospinnability of lignin/polyvinylpyrrolidone (lignin/PVP) solution as well as flexibility and uniformity of the resulting lignin-based carbon nanofibers. By treating with phosphoric acid, the carbon nanofibers obtained are doped with phosphorus, resulting in improved surface wettability and electrochemical properties. In the range of 0–60 wt% H 3 PO 4 , phosphorus-doped (P-doped) carbon nanofibers prepared from 40 wt% H 3 PO 4 (PCNFs40), as electrode materials, show the highest specific capacitance of 153.9 F/g at a current density of 0.1 A/g. To enhance electrochemical performance of the P-doped carbon electrodes, we further develop zeolite imidazole framework-67 (ZIF-67)/P-doped carbon nanofiber hybrid materials (ZIF-67@PCNFs40) by simple deposition of ZIF-67 on PCNFs40 at ambient temperature. After calcination at 300–400 °C in air, ZIF-67 on ZIF-67@PCNFs40-300C and ZIF-67@PCNFs40-400C is transformed into cobalt oxide. Due to their high specific surface area (507.3 m2/g) and abundance of active surface elements, ZIF-67@PCNFs40-300C exhibit high specific capacitance (307.7 F/g at a current density of 0.1 A/g in a 2.0 M H 2 SO 4 electrolyte) with excellent cycling stability (99.9 % capacitance retention after 5,000 cycles). The ZIF-67@PCNFs40-300C show a great potential as flexible and binder-free hybrid electrodes for high performance supercapacitor with an energy density as high as 42.7 Wh/kg at a power density of 270 W/kg. [ABSTRACT FROM AUTHOR]

• The nucleophilic sites of hydrophobic ADN can coordinate with Zn2+ ion, which can release the bound H 2 O molecules in the Zn2+-solvation sheath, disrupt the HB network of water molecules and form a dynamic cross-linked hydrophobic network. • The dynamic hydrophobic network confines H 2 O molecules within the grid to form many "dynamic water microdomain", further inhibiting the activity and decomposition of H 2 O. • DFT calculation indicates ADN has larger adsorption energy on Cu than H 2 O, which implies that ADN can preferential adsorb on the surface of electrodes to regulate the Zn plating/stripping process. • The addition of ADN can significantly affect the H-Bond orientations within H2O molecules, which suggests that ADN may play a crucial role in modulating the dipole–dipole interactions between water molecules, thereby affecting its behavior in the electrochemical processes. • The Microscopic structure of the EDL under the same negative polarization based on the MD calculation, proving some ADN molecules infiltrate the IHP and expel some H 2 O molecules in IHP, inducing the increase of Zn2+ ions and OTF- anions in IHP. The bonding state of H 2 O molecules determines the properties of electrolyte, which strongly impacts on the performance of electrode/battery. In this work, we utilized the nucleophilic sites at two ends of the hexanedinitrile (ADN) to coordinate with Zn2+ ions, which could release the bound H 2 O molecules in the Zn2+-solvation sheath and form a dynamic cross-linked hydrophobic network. This dynamic hydrophobic network can disturb the hydrogen bonds (H-bonds) between H 2 O molecules, and confine H 2 O molecules within the grid to form many "dynamic water microdomain", further inhibiting the activity and decomposition of H 2 O. Theoretical calculations, Raman and NMR spectra verify that the water microdomain, solvation-sheath structure, electrochemical double layer (EDL) and the bonding state of H 2 O molecules can be regulated by the ADN additive. As a result, significant improvements in stability of electrode/battery and dendrite suppression can be achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel boron-doped bimetallic carbon felt electrode was successfully prepared. • sp3/sp2, C O and M–B were the main active sites. • O 2 − and OH played a dominant role in the DOX removal process. • Three possible pathways for DOX were identified by LC-MS and DFT calculations. • The treated DOX solution reduced the toxicity to the growth of E. coli and mung bean. The pervasive presence of antibiotics in the environment poses ecological risks and jeopardizes human health. Herein, a simple one-step hydrothermal method was used to prepare a boron-doped (B-doped) bimetallic carbon felt as a cathode for the heterogeneous electro-Fenton (HEF) system. In the HEF process, the modified electrode (B-Co/Fe@CF) demonstrated exceptional efficiency in degrading the target pollutant doxycycline (DOX), owing to its maximal degree of defect and minimal electrochemical impedance. In addition, XPS and structure–activity relationship analysis results revealed that the superior performance of the modified electrode stemmed from the predominant influence of sp3/sp2, C O and metal-boron (M–B) groups in initiating the production of H 2 O 2 and the consequent formation of reactive oxygen species (ROS). Meanwhile, the introduction of non-metallic boron species significantly accelerated the sustainable cycling of Co(Ⅱ)/Co(Ⅲ) and Fe(Ⅱ)/Fe(Ⅲ). The quenching and probe experiments suggested that the radicals O 2 − and OH significantly contributed to the elimination of DOX. Moreover, the advanced B-Co/Fe@CF-HEF system exhibited remarkable versatility, stability and effectiveness throughout the degradation process. Three pathways for the degradation of the pollutants were identified using density functional theory (DFT) calculations and LC-MS detection. Additionally, the treated DOX solution significantly reduced the toxicity to the growth of E. coli and mung bean in actual toxicity experiments. This research presented a novel outlook on developing the B-doped metal catalysts for efficient degradation of pollutants and showcased promising applications in organic wastewater treatment. [ABSTRACT FROM AUTHOR]

Bismuth is considered to be a promising anode for sodium-ion batteries due to its low voltage plateau and high volumetric capacity. However, the large volume variation during alloying/dealloying leads to electrode pulverization and performance degradation, especially under high current densities. Herein we propose a lattice-confined localized alloying reaction mechanism to solve the above issues. By chemically embedding Bi atoms in a rigid layered ▪ host framework, the alloying reaction of Bi is spatially and kinetically confined within the ▪ interlayer, allowing for complete recovery of the Bi 0.67 TaS 2 crystal structure after desodiation. The as-prepared Bi 0.67 TaS 2 anode exhibits superior rate performance, achieving capacities of 256 mAh g ▪ at 1 C and 186 mAh g ▪ at 150 C, along with remarkable long-term cycling stability for maintaining 153 mAh g ▪ after 20000 cycles at 150 C. This work demonstrates that the localized alloying mechanism enabled by lattice confinement significantly contributes to both rate and cycling performance, which is expected to provide insights into electrode design for future fast-charging batteries. • A new Bi 0.67 TaS 2 anode is designed via chemically integrating electrochemical-active atomic Bi and 2D TaS 2 host framework. • Bi 0.67 TaS 2 undergoes a reversible electrochemical reaction with its crystalline phase being recovered after recharging. • A lattice-confined localized alloying mechanism is proposed. • Bi 0.67 TaS 2 exhibits superior rate performance up to 150 C and long-term cycling stability for 20,000 cycles. [ABSTRACT FROM AUTHOR]

• Graphene integration into cathodes ensures percolated diffusion paths for lithium-ions. • Graphene acts as a mixed ion–electron conductor for composite cathodes. • DFT analysis reveals that AB-stacked graphene has the potential to improve lithium diffusion. Significant progress has been achieved in advancing all-solid-state lithium-sulfur batteries through the development of sulfide solid electrolytes. Nonetheless, a challenge lies in creating a percolated ion–electron conduction path with intimate contact between charge carriers throughout the cathode which is crucial for enhancing overall efficiency and addressing issues related to slow kinetics and impedance during battery operation. This study introduces a framework elucidating how the integration of graphene enhances electrode performance by refining ionic diffusion pathways. An idealized ionic diffusion pathway characterized by a continuous ionic network, facilitating minimum diffusion distances, is proposed. Through a parametric study substituting portions of ionic and electronic conductive agents with graphene, the impact on total ionic and electronic conductivity of positive electrodes was comprehended. The findings underscore the critical role of optimum graphene content, which fills the gaps between ionic conductive materials and creates the shortest diffusion paths for ions and electrons. While incorporating graphene into cathode electrodes is not novel, it is noteworthy that graphene, as a mixed ion–electron conductive material, significantly enhances ion mobility due to its 2D structure, addressing a crucial aspect of cathode performance. Upon achieving optimum composite formulation, empirical findings demonstrate substantial performance improvement, including a 17.7% increase in initial capacity and a remarkable 21% enhancement in capacity retention compared to electrodes without graphene. [ABSTRACT FROM AUTHOR]

• The thermoelectric augmentation effect improves the electrochemical performance. • The specific capacity of the n-type Cu 0.3 Ag 1.7 Se anode is increased by 208%. • The mechanism is that carriers accelerate the interface electrochemical reaction. • Inappropriate conductive types can inhibit electrochemical performance. • Thermoelectric materials of different conductive types confirm the universality. Conventional methods to enhance the performance of electrode materials include morphological modification and defect engineering, but the limited number of active sites for the electrode remains a huge obstacle to achieving high-performance supercapacitors. In this work, we proposed a strategy to improve the electrode performance under the condition of limited active sites through the thermoelectric effect, and designed thermoelectric electrodes of the p-type Fe 0.3 Co 0.7 Sb 3 cathode and the n-type Cu 0.3 Ag 1.7 Se anode for supercapacitors, respectively. In particular, the charge carriers generated by the thermoelectric effect accelerate the electrochemical reaction process at the interface between the thermoelectric electrode and the electrolyte under the temperature difference (ΔT) condition, thus increasing the specific capacity of the electrode. The p-Type Fe 0.3 Co 0.7 Sb 3 cathode and the n-Type Cu 0.3 Ag 1.7 Se anode exhibit a 150% and 208% increase in the specific capacity, respectively. Furthermore, electrodes with different conduction types and various thermoelectric properties, such as n/p-type bismuth telluride and n/p-type half-Heusler thermoelectric materials are also studied, confirming the universality of the above phenomenon in thermoelectric electrodes. This work provides a universal route for the thermoelectric effect to promote the energy density of supercapacitors used in high temperature difference environments. [ABSTRACT FROM AUTHOR]

Redox-active "structural pillar" molecular doping strategy boosts the electrode performances of 3D honeycomb-structured polyaniline hydrogel in flexible supercapacitors. [Display omitted] • A redox-active and large-sized molecular dopant is integrated to 3D honeycomb porous polyaniline (PANI) hydrogels. • It works as both the "structural pillar" and pseudocapacitive sites towards PANI-based flexible supercapacitors. • The energy storage mechanism is monitored by in-situ infrared and Raman spectroscopy in detail. To coordinate flexibility to electrodes without sacrificing their electrochemical properties is critical for the development of wearable supercapacitors (SCs). Polyaniline (PANI) is well-known pseudocapacitive electrode material due to its high conductivity and different oxidation states upon switchable structures. However, its rigid conjugated backbone and structural instability caused by repeated doping/de-doping during cycling severely impede its utilization in flexible SCs. Herein, we deploy a directional freezing and redox-active "structural pillar" molecular doping strategy to boost PANI-based flexible SCs with high performance. The directional freezing strategy constructs an interconnected 3D honeycomb hydrogel structure with PANI nanofibers, which guarantees fast ion diffusion and electron transport and meanwhile exposes abundant active sites. The large-sized dopant 2-amino-4-bromoanthraquinone-2-sulfonic acid sodium (AQNS) is used as the structural pillar to alleviate the structural instability of PANI during cycling and provides additional pseudocapacitance arising from its redox active quinone groups. Moreover, the negatively charged −SO 3 − on AQNS can further interact with H+ in the electrolyte to act as an internal proton reservoir, assisting the protonation of –NH- and −N = in PANI to facilitate its charge storage process. Consequently, the PANI-AQNS electrode achieves a high specific capacitance of 578 F g−1 at 1 A g−1 and its symmetric SCs exhibit a specific capacitance of 199 F g−1 at 0.5 A g−1 with an energy density of 13.61 W h kg−1 at a power density of 175 W kg−1. Upon 2000 cycles of dynamic deformations, the SCs can still maintain above 90 % of the initial capacitance, verifying their excellent flexibility-relevant property. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hollow carbon spheres (MHCS) with controlled sheath thickness and nanochannels. • The MHCS separated 3D MXene/MHCS electrode by one-step filtration. • Nanochannels on the sphere sheath help the fast diffusion of ions in electrolyte. • Conductive sheath reduces the contact resistance between MXene sheets. The development of electrode materials with a hierarchically porous structure and good electrical connection is key to improving the charging-discharging rate and energy density of supercapacitors. However, the restacking issue of two-dimensional nanomaterials, such as MXene, seriously hinders the diffusion of electrolyte ions. Different from the extensively used sacrificing template method, a hierarchical heterostructure of electrically conducting mesoporous hollow carbon spheres (MHCS) and MXene composite electrode is designed and achieved through simple vacuum filtration without further template removing procedures. This direct preparation strategy not only effectively improves the specific surface area of the electrode but also enhances the abundant surface pores and good conductivity of MHCS, improving the penetration of the electrolyte solution and shortening the ion transport path, leading to a pronounced improvement in specific capacitance and rate performance of the electrodes. Additionally, the influence of sheath thickness of MHCSs on ion transfer rate is deeply discussed. The introduction of carbon nanotubes (CNTs) further improves conductivity and stability while maintaining good flexibility. Consequently, the MXene/MHCS/CNT film delivers a high specific capacitance (395F g−1 at 2 mV s−1), outstanding rate performance (70.9 % at 1000 mV s−1), and excellent cycling stability (98.3 % capacity retention after 10,000 cycles). Furthermore, the assembled symmetric supercapacitor provides a maximum energy density of 14.48 Wh kg−1. This work provides a quick and effective approach for constructing high performance 3D MXene architectures for fast ion transfer electrodes. [ABSTRACT FROM AUTHOR]

• Nanoporous NiO films prepared by electrodeposition-dealloying method. • Decoration of Ag nanoparticles on nanoporous NiO films by photoreduction. • The enhanced specific capacitance of 3592.9 F/g at 1 A/g for nanoporous NiO-Ag. • An asymmetric supercapacitor NiO-Ag//AC delivered 85.41 Wh/kg at 36600 W/kg. Nanoporous NiO films are prepared by electrochemical dealloying the Zn-Ni alloys electrodeposited on Ni substrates followed by self-oxidizing method. The electrodeposition-dealloying parameters are investigated. The optimal nanoporous NiO film exhibits a specific capacitance of 1212.0 F/g at 1 A/g. The capacitance retention rate can reach 71.9 % at 20 A/g. The improved electrochemical properties are attributed to the hierarchical porous structure, which can provide large specific surface areas with enough exposed active sites and enhance the mass transport. On the basis of this, nanoporous NiO films are decorated with Ag nanoparticles with an average size of 50.6 nm using photoreduction method. Owing to the good ohmic contact between Ag and NiO, the nanoporous NiO-Ag films possess an increased specific capacitance up to 3592.9 F/g three times higher than the nanoporous NiO film. The capacitance retention rate reaches 84.5 % at 20 A/g. An asymmetric supercapacitor NiO-Ag//AC exhibits an energy density of 116.88 Wh/kg at 1720 W/kg. An energy density of 85.41 Wh/kg is maintained at 36600 W/kg. These boosted electrochemical performances are mainly owing to the synergistic effects of unique hierarchical porous structure and high electronic conductivity. This study provides a new approach to high performance electrodes for supercapacitors. [ABSTRACT FROM AUTHOR]

MXene-integrated N-doped cavity-interconnected porous carbon nanofibers flexible film with excellent energy storage performance was prepared by a non-pre-oxidation synthesis strategy combining electrospinning and metal–organic framework derivatization. [Display omitted] • The flexible carbon film is constructed by MXene-integrated N-doped cavity-interconnected porous carbon nanofibers. • The non-preoxidation synthesis strategy overcomes the MXene oxidation and active site loss caused by the flexible carbon film during the preparation process. • The flexible carbon film exhibits a high energy density of 26.2 Wh kg−1 at 500 W kg−1 and good capacitance retention (96.3 %) after 10,000 charge–discharge cycles. • This study develops an effective general strategy for the preparation of embedded carbon nanofiber flexible film. Although the flexible carbon film integrated with MXene has been proven to be a new generation of supercapacitor material with good energy storage prospects, the MXene oxidation and the lack of active sites during the preparation of the carbon film can lead to irreversible capacity loss. Herein, a flexible carbon film constructed by MXene-integrated N-doped cavity-interconnected porous carbon nanofibers was prepared by a non-pre-oxidation synthesis strategy combining electrospinning and metal–organic framework derivatization. This flexible carbon film overcomes the oxidation problem of MXene during the stabilization of polyacrylonitrile, and the derived porous structure of cavity interconnection exposes more active sites. Due to its unique structural characteristics and ideal chemical composition, this independent flexible carbon film exhibits significantly enhanced electrochemical performance as an electrode material for supercapacitors. It exhibits an energy density of 26.2 Wh kg−1 at a power density of 500 W kg−1, and a capacitance retention rate of 96.3 % after 10,000 charge–discharge cycles. This study provides a unique strategy for the preparation of high-performance flexible carbon films, and this technology can also be extended to other integrated CNF composites for the design of high-performance supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

The snowflake ZCO/SF-0.2 formed by SrF 2 modification of ZnCo 2 O 4 has excellent electrochemical properties. [Display omitted] • The stable cathode materials of ZCO/SF-X supercapacitor with different morphologies were synthesized by modifying ZnCo 2 O 4 with SrF 2. • The possibility of successful composite of SrF 2 and ZnCo 2 O 4 is confirmed by DFT theory, which proves that the composite has more stable structure and higher electrical conductivity. • The snowflake ZCO/SF-0.2 maintained 100% capacitance retention and Coulomb efficiency after 21,000 cycles of three electrodes, and 91.67% capacitance retention and 100% Coulomb efficiency after 40,000 cycles of two electrodes. • The ZCO/SF-0.2 and AC assembled HSC has an energy density of 63.28 Wh/kg at a power density of 850.03 W/kg and an impressive energy density of 40.85 Wh/kg at a power density of 8500.58 W/kg. Electron/ion transport dynamics and cyclic stability are the keys to research supercapacitor devices. In this paper, we designed the snowflake ZnCo 2 O 4 /SrF 2 -0.2 composite by a simple one-step hydrothermal process. By changing the number of metal sources, adjusting the core–shell, adjusting the interaction, and exerting the synergistic effect between materials, ZCO/SF-X composites with different morphologies were synthesized. The feasibility of the composite between the two materials is discussed by DFT theory. The overall energy of the successful composite of ZnCo 2 O 4 and SrF 2 is lower, and a more stable structure is formed. When ZnCo 2 O 4 is combined with SrF 2 , the carrier density near the Fermi level is enhanced, and the electrical conductivity is enhanced, thus facilitating charge transport. Specifically, the snowflake ZCO/SF-0.2 active electrode has a specific capacitance of 1086C/g at a specific current of 1 A/g. After more than 21,000 cycles, the specific capacitance is maintained at 100 %, and the coulomb efficiency is maintained at 100 %, showing excellent cycle stability. The assembled HSC has an energy density of 63.28 Wh/kg at a power density of 850.03 W/kg and an impressive energy density of 40.85 Wh/kg at a power density of 8500.58 W/kg. Importantly, after 40,000 cycles, the specific capacitance is maintained at 91.67 %, which is further confirmed by the density universal function calculation. The snowflake ZCO/SF-0.2 electrode synthesized by a simple method overcomes the inherent volume expansion problem of the material, forms a more stable structure, and shows unprecedented cyclic stability. This strategy provides a new method and idea for improving the performance of electrode materials, and opens up a new road for efficient electrode materials. Guidance is provided for designing devices for energy conversion and storage. [ABSTRACT FROM AUTHOR]

• Established the quaternary phase diagram FePO 4 -LiFePO 4 -NaFePO 4 -KFePO 4 by DFT for the first time. • The competitive mechanism of alkali ions in FePO 4 during extraction from a salt lake is revealed. • Na 2/3 FePO 4 phase is the main reason for to decreased cyclability of FePO 4 for lithium recovery in brines. • Proposed an innovative FePO 4 regeneration process to enhance electrode performance and lifespan. The rapid expansion of lithium battery applications has resulted in a shortage of lithium resources, prompting researchers to focus on the electrochemical extraction of lithium from water resources using FePO 4 as the host material. However, a large amount of alkali metal impurity ions in brine leads to irreversible capacity loss, limiting the industrial application of FePO 4 materials in lithium extraction. The mechanism of alkali metal ions' influence on FePO 4 materials remains unclear. To address this issue, the quaternary phase diagram of FePO 4 -LiFePO 4 -NaFePO 4 -KFePO 4 and the diffusion barriers of lithium/sodium ions in FePO 4 were obtained for the first time based on the theoretical calculation of density functional theory (DFT). DFT and X-ray diffraction (XRD) refinement revealed that the inability to remove Na 2/3 FePO 4 from the FePO 4 is a critical issue affecting electrode recyclability. An innovative electrode regeneration process was proposed to enhance the lifespan of FePO4 material. The Na 2/3 FePO 4 impurity was converted to LiFePO 4 using K 2 S 2 O 8 abstersion and 0.1 mol/L LiCl lithiation regeneration process. After five rounds of regenerations, the total lithium extraction of the material could still reach 80.18 % of the extraction of the brand-new electrode, demonstrating the multiple reuses of the host material and cost savings. These innovative discoveries can advance the industrial application of electrochemical lithium extraction from FePO 4 electrode materials. [ABSTRACT FROM AUTHOR]

• A cascade dual-enzyme transformation strategy based on CRISPR-Cas12a and Mg2+-DNAzyme. • The trans -cleavage activity of CRISPR-Cas12a could be regulated by ZEN-Apt. • NH 2 -MnO 2 /Pd@AuNBs has larger surface area and higher electrical conductivity. • PtPd@Fe 3 O 4 -MB as signal label improves sensitivity and simplifies operations. The combination of the CRISPR/Cas system and biosensing is of profound significance in small molecule diagnostics. Herein, we report a cascade dual-enzyme transformation strategy for ultrasensitive analysis of zearalenone (ZEN) by utilizing the CRISPR/Cas12a trans -cleavage activity and DNAzyme amplification. NH 2 -MnO 2 /Pd@Au NBs nanocomposites are greatly promising electrode modification material for improving electrode sensing performance. PtPd@Fe 3 O 4 nanocomposites are synthesized as signal label materials to load the electroactive molecule methylene blue (MB). The recognition of ZEN target and aptamer is converted into DNA signal to regulate the trans -cleavage activity of the CRISPR/Cas12a on Mg2+-DNAzyme probes. After that, in the presence of DNAzyme probes and Mg2+, the MB signal changes caused by Mg2+dependent DNAzyme-assisted catalytic cleavage of signal labels on the electrode surface are evaluated. The quantitative detection of ZEN is ultimately achieved. Under optimal conditions, the as-prepared electrochemical aptasensor shows a wide linear detection range of 1 × 10-5 to 10 ng·mL−1, and the detection limit is 6.27 × 10-6 ng·mL−1. Moreover, the constructed aptasensor exhibits satisfactory selectivity, stability and repeatability, which also has a wide application prospect in the real sample analysis. [ABSTRACT FROM AUTHOR]

• A novel Fe/Mn@CF composite electrode is fabricated for the activation of sulfite. • Fe/Mn@CF-sulfite system exhibits satisfied degradation activity and stability. • Both free radical and non-free radical pathways boost pollutant degradation. • The presence of redox cycles of Fe and Mn promotes the activation of sulfite. • The synergistic interactions of electric field and metals lead to efficient sulfite activation. Sulfite has been proven to promote advanced oxidation processes (AOPs) to achieve low-cost and efficient degradation of contaminants, serving as an alternative to persulfate. In this study, a novel composite Fe/Mn@carbon felt (CF) electrode was successfully constructed to remove carbamazepine (CBZ). The capacity of the Fe/Mn@CF anode to activate sulfite was evaluated under various electrode preparation conditions and operating parameters. Results clearly indicated that the complete removal of CBZ was achieved in Fe/Mn@CF anode activated sulfite system under the specific conditions including Na 2 SO 4 electrolyte concentration of 50 mM, sulfite dosage of 1 mM, initial pH of 7, and current density of 1 mA/cm2. The capacity of Fe/Mn@CF anode for sulfite activation was further presented by its excellent reusability and stability in terms of CBZ removal and metal ion release. Both radical and non-radical pathways were significantly contributed to the CBZ removal, including OH, SO 4 · - , O 2 · - , 1O 2 , and other reasons. Density functional theory (DFT) calculations demonstrated that Fe-Mn bimetals effectively promoted sulfite activation, with the electric field further boosting the process of Fe-Mn valence cycle and oxidation. Overall, the novel Fe/Mn@CF activated sulfite system exhibited outstanding performance and had great potential for sustainable use in removing organics. [ABSTRACT FROM AUTHOR]

• Recent advances in discovery and performance prediction of energy storage materials relying on ML. • An overview of the current status and dilemmas of ML databases commonly used in energy storage materials. • ML in energy storage material discovery and performance prediction: typical applications and examples. • Dilemmas to be faced in the development of ML-assisted or led energy storage materials, and corresponding prospects. Energy storage material is one of the critical materials in modern life. However, due to the difficulty of material development, the existing mainstream batteries still use the materials system developed decades ago. Machine learning (ML) is rapidly changing the paradigm of energy storage material discovery and performance prediction due to its ability to solve complex problems efficiently and automatically. Various excellent works are constantly emerging in the field of ML assisted or dominated development of energy storage material, such as exploring of new materials, studying of battery performance, investigating of battery aging mechanism. In this paper, we methodically review recent advances in discovery and performance prediction of energy storage materials relying on ML. After a brief introduction to the general workflow of ML, we provide an overview of the current status and dilemmas of ML databases commonly used in energy storage materials. The typical applications and examples of ML to the finding of novel energy storage materials and the performance forecasting of electrode and electrolyte materials. Furthermore, we explore the dilemmas that will be faced in the development of applied ML-assisted or dominated energy storage materials and propose a corresponding outlook. This review systematically summarizes the current development of ML-assisted energy storage materials research, which is expected to point the way for its further development. [ABSTRACT FROM AUTHOR]

• Using the thermo-mechanical synergistic effect to control the entire cell interface is proposed for SOFCs. • The novel electrode exhibits no obvious attenuation during the rapid thermal cycling between 400–700 °C for 25 times. • A symmetrical cell with LSCF@GDC&NM electrode reaches 442 mW cm−2 peak power density at 0.57 V and 800 °C. Solid oxide fuel cells (SOFCs) are efficient and clean energy conversion devices, but one of the major challenges for their marketization is the instability of different component materials under high temperature operating conditions. The existence of a certain internal stress gradient between materials with different thermal expansion characteristics in the process of SOFCs from low temperature assembly to high temperature use is the main reason of this instability, leading to the inability of SOFCs to repeat start-stop and the rapid decay of long-term stability performance. To improve these problems, a creative concept of fuel cell interface overall regulation is proposed, simplifying the complex interface between different components of SOFCs into a unified and adjustable quasi-zero difference thermal expansion interface. The composite of high catalytic activity electrode material and high stability negative thermal expansion material is used for electrolyte support structure symmetrical cell, which makes the whole cell "sandwich" structure thermally and mechanically compatible. As a concept verification, the classic high catalytic performance electrode material La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF), Gd 0.2 Ce 0.8 O 2-δ (GDC) and NdMnO 3 (NM) negative thermal expansion material with high chemical stability and mechanical stability were composited in equal proportions to form LSCF@GDC&NM electrode as the symmetrical electrode. After equal proportion compositing, the thermal expansion curve of LSCF@GDC&NM material can highly coincide with the thermal expansion curve of GDC, making the single cell with LSCF@GDC&NM electrode can withstand 25 power thermal cycles without significant performance decay, achieving 442 mW cm−2 at 800 °C and maintaining stably for 140 h without any degradation. These results show that using negative thermal expansion material to regulate electrode strategy is expected to make a whole zero difference thermal fuel cell configuration. [ABSTRACT FROM AUTHOR]

• A coal-based activated carbon foam with a unique 3D porous structure was successfully prepared. • The activated carbon foam is firstly reported as a rigid free-standing electrode for SCs. • The symmetric device delivers a volume energy density of 10.23 mWh cm−3 at 31.78 mW cm−3. • The symmetric device achieves an outstanding cycling stability of 100 % after 40 000 cycles. A free-standing electrode material is a competitive candidate for supercapacitor due to its excellent capacity and volumetric energy density. Currently, most of the studies are focused on the preparations and performances of flexible free-standing electrode materials, whereas few on the development of rigid free-standing electrode materials. Herein, a vitrinite concentrate of fat coal is used as a raw material and carbon black as an addition agent to prepare a carbon foam by way of high-pressure pyrolysis. The prepared carbon foam is activated by KOH solution to further achieve an activated carbon foam by which we have fabricated a rigid free-standing electrode material. The assembled symmetric device with the rigid free-standing electrode material demonstrates an extremely high areal specific capacitance of 2304.41 mF cm−2 at 4 mA cm−2, an outstanding cycling stability of 100 % after 40 000 cycles, and an excellent volume energy density of 10.23 mWh cm−3 at 31.78 mW cm−3. These fascinating electrochemical performances of the electrode material are attributed to unique 3D interconnected porous structure of the activated carbon foam. The micron-sized 3D interconnected pores facilitate the transport of electrolyte ions within the electrodes. Meanwhile, micropores on the 3D interconnected pore wall provide abundant active sites for electrolyte ions. [ABSTRACT FROM AUTHOR]

• Inorganic Cu 2 GeS 3 nanocrystals are utilized as hole transporting layer in C-PSCs. • Cu 2 GeS 3 could effectively extract photo-generated holes and suppress the charge carrier recombination. • C-PSC with a champion PCE of 19.0% is demonstrate. Hole transporting layer (HTL) is indispensable for promoting the power conversion efficiency (PCE) and device stability of perovskite solar cells (PSCs), especially for the carbon electrode based PSCs (C-PSCs). Compared with the large amount of organic HTLs, which are available for metal electrode based PSCs, the inorganic HTLs for C-PSCs are relatively scarce. In this study, we successfully synthesized Cu 2 GeS 3 nanocrystals with spherical shape and well dispersibility, and further explore their potential to function as inorganic HTL for C-PSCs. The Cu 2 GeS 3 HTL can greatly improve the PCE of C-PSCs to 19.0 %, which is enhanced by 36.3 % compared with that (PCE = 13.9 %) of HTL-free C-PSCs. The reported PCE in our study is among the highest PCEs for C-PSCs with inorganic HTL, therefore, our study indicates that Cu 2 GeS 3 nanocrystals are excellent inorganic HTL for C-PSCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel ZNRs/GNWs/Papyex hybrid electrode reveals the unique open spiky structure. • Synergistic effects between ZNRs and graphene nanowalls enhanced energy storage. • Introduced oxygen vacancies evidently expanded active sites of composite system. • The mechanism of OV-assisted supercapacitive enhancement was investigated. Vertical graphene nanowalls (GNWs) have emerged as a highly promising architectural structure, offering a vast surface area teeming with active sites and expediting ion diffusion. In our relentless pursuit of bolstering their specific capacitance, we unveil a groundbreaking supercapacitive augmentation, incorporating defect-engineered ZnO nanorods (ZNRs) branching out from the GNWs. The realization of this hierarchical structure is achieved through a meticulous multi-step process, featuring inductively coupled plasma-chemical vapor deposition, magnetron sputtering, and hydrothermal synthesis. The presence of oxygen vacancy (OV) defects within the ZNRs, induced by argon annealing, has been characterized using X-ray photoelectron spectroscopy (XPS). The emergence of OV defects below the conduction band of the ZNRs results in a narrowing of the bandgap within the hybrid structure, thereby enhancing its conductivity and increasing the reaction sites. The capacity of the ZNRs/GNWs hybrid electrodes were evaluated in an aqueous KOH electrolyte solution, operating within a voltage range of 0.5 V and at a current density of 0.1 mA cm−2. This assessment yielded an area capacitance of 21.45 mF cm−2, signifying a 1.5-fold increase in capacitance compared to GNWs grown on graphite sheets. The ZNRs/GNWs hybrid demonstrates remarkable electrochemical performance and exhibits substantial potential for energy storage applications. Our work is expected to offer valuable insights for the enhancement of electrochemical properties in various composite and hybrid materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen-rich OCNT-80/CB metal-free cathode for MFC-Fenton system was fabricated. • The enrichment of dominant bacteria provides long-term stable power supply. • Metal-free MFC-Fenton system is efficient at a wide pH range. • The system can treat actual wastewater with double-electrode and double-efficiency. • The study conforms to the environmental sustainability, no secondary pollution. Fenton coupled microbial fuel cells (MFCs) used for antibiotic pollution purification are limited by energy recovery and metal leakage of electrode. Here, we constructed a two-compartment bio-electro-Fenton (MFC-Fenton) with biological anode and Fenton cathode, which using carbon nanotube based on carbon brushes (OCNT-80/CB) with active centers rich in oxygen-containing functional groups as metal-free cathode. The results show that C = O locked environmental oxygen in the cathode can in-situ use the electrons produced by the anode through two-electron oxygen reduction reaction (2e− ORR) synthesize H 2 O 2. •OH is further generated under activation of H 2 O 2 , achieving effective degradation of tetracycline (TC) in the cathode chamber. This study breaks through the limitations of poor pH adaptability and environmental secondary pollution caused by metal dissolution. Moreover, with the advantageous features of oxygen-containing functional groups active centers, good conductivity, and cyclic stability, the OCNT-80/CB achieves a maximum power density increased by 79.4 % as compared to that of the CB control. More notably, Microbial analysis further indicated that OCNT-80/CB electrode could simultaneously enhance Proteobacteria and Firmicutes abundance in bioanode. Dominant bacteria can self-metabolize environmental wastewater generate and recycle green energy. This study proved that careful structural design of cathode could promote the electrode performance. MFC-Fenton can be a competitive technology to enhance wastewater treatment and energy recovery simultaneously. [ABSTRACT FROM AUTHOR]

• This work designed a structure embedding WS 2 sheets parallel to SnS sheets. • SnS/WS 2 @C was obtained by the one-pot/multi-step solvothermal method. • Parallelly oriented WS 2 sheets provide K+ channels and stabilize the structure. • SnS/WS 2 @C exhibits superior electrochemical performance. Tin sulfide (SnS) exhibits the potential to be used as a superior-performance electrode material for potassium ion batteries. However, serious volume expansion and poor ion transport capacity hinder the applications of SnS. In order to solve the above problems, this work designed a structure that parallel WS 2 sheets were embedded in SnS sheets (SnS/WS 2 @C). SnS/WS 2 @C displayed excellent kinetic properties and stability when applied to anode materials for potassium ion batteries, as well as a high reversible capacity. SnS/WS 2 @C maintains a superior specific capacity of 619 mAh g−1 after 100 cycles at 0.2 A g−1 and 210 mAh g−1 at 10 A g−1. Such excellent performance is attributed to the fact that parallelly oriented WS 2 sheets provide fast channels for the transportation of potassium ions, which significantly improves the kinetic performance of the electrode, and can play an anchoring role for products in the process of charging and discharging by virtue of its excellent stability to effectively prevent structural fragmentation. This work provides new ideas for improving ion diffusion and enhancing the structural stability of transition metal layered compounds while maintaining the capacity advantage. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOF@MXene composites are renowned SC electrodes with versatile morphology and promising prospect. • Various synthesis concepts are proposed based on different features of MOF/MXene. • Structural-capacity relationship is synthetically overviewed on MOF@MXene composites. • Potential MOF precursors and MXene substrates are proposed for promising SC electrodes. Engineering metal–organic framework (MOF)@MXene hybrid composites as capable supercapacitor electrodes is one of the most prevalent research hotspots in the contemporary energy conservation stage. Electrochemical performances of MOF@MXene electrodes are greatly dependent on their structural property, mainly deriving from the MOF characters, synthesis routes and the structural morphology of the resultant composites. In this review, a comprehensive summarization of MOF@MXene-based hybridized electrodes is described from two aspects: morphology regulation and electrochemical evaluation. Metal ions and organic ligands tuning the structural properties of MOF, and different synthesis concepts for boosting the coordination bond and/or facilitating the framework effect of MOF on the MXene distribution have been concluded. A systematic summarization, comparison and prospection about the fate of MOF@MXene hybridized electrodes is achieved, including MOF varying in metal ions and organic ligands, preparation protocols, evaluation strategies and electrochemical performances, as well as multi-application prospects of MOF@MXene-based electrodes. Furthermore, the limitations, differences and new blueprints for the development of MOF@MXene composites are discussed. [ABSTRACT FROM AUTHOR]

Through comprehensive analyses, the configuration of sulfur atoms in molybdenum sulfide plays a significant role in determining their electrochemical performance in both anode and cathode materials. We also introduce carbon composites to address inherent limitations of molybdenum sulfides. Our investigation contributes valuable insights to the development of sustainable energy technology for the future. [Display omitted] • Molybdenum sulfides with varying Mo and S ratios were prepared. • [Mo 3 S 13 ]2− exhibit a unique single-step Li-ion storage mechanism. • The research highlights the critical role of S atom configuration in electrochemical behavior. • Mo 3 S 13 @rGO enhances rate capability and ensures a stable cycling lifespan. • Molybdenum sulfides have the potential to serve as both anode and cathode materials. Molybdenum sulfides are highly regarded as conversion-type electrodes with exceptional performance potential in lithium-ion batteries (LIBs). However, elucidating their lithium (Li) storage behavior has proven challenging due to the intricate sulfur (S) coordination with molybdenum atoms, which has impeded the realization of high energy densities in future Li storage systems. In this study, we investigate the electrochemical redox reaction pathways of molybdenum sulfide, specifically exploring the impact of various S configurations, including terminal, bridging, and apical S. We employ a comprehensive approach, involving extensive electrochemical measurements and depth X-ray photoelectron spectroscopy (XPS) profiling. In contrast to the multi-step conversion reactions observed in MoS 2 , sulfur-enriched molybdenum sulfides exhibit a unique single-step Li-ion storage mechanism. As a consequence of the pronounced effect of S configuration on the activation energy barrier during charging and discharging, the redox reaction voltage with Li ions exhibits variations. This versatility verifies that molybdenum sulfides have the potential to serve as both anode and cathode materials in lithium-ion batteries. Furthermore, we propose the incorporation of reduced graphene oxide (rGO) composites to address inherent limitations of molybdenum sulfides, including low electrical conductivity and irreversible reactions. The robust interaction between molybdenum sulfides and oxygen functional groups in rGO enhances rate capability and ensures a stable cycling lifespan. Through this systematic investigation, we suggest a comprehensive insight into the electrochemical reaction pathways governing Li storage behavior in molybdenum sulfides with distinct S configurations. This contributes to the fundamental understanding of these materials and their potential applications in advanced energy storage systems. [ABSTRACT FROM AUTHOR]

The high fractal-dimensional graphene ribbons construct spatially conductive and mechanically reinforced networks, but without blocking the ion transport channels, when used as the conductive agent for Si-based electrodes, enabling a significantly improved areal capacity with good cycle stability. [Display omitted] • Novel high fractal-dimensional conductive agent was developed for Si electrode. • Their spatial extensibility ensures highly conductive and reinforced networks. • The ribbon structure facilitates ion transport by forming abundant channels. • High-mass-loading Si electrode with good performance is achieved. Constructing stable Si electrodes with high areal capacity is crucial for improving the total energy density of lithium ion batteries (LIBs). However, it remains challenging because the poor intrinsic conductivity and serious pulverization of Si usually lead to the active material falling-off from the conductive network. Herein, we demonstrate novel spatially extended graphene ribbons with a high fractal-dimension structure (HFGR-400), which can construct highly conductive and mechanically reinforced networks when used as the conductive agent for Si electrodes. The HFGR-400 added electrode shows 1.5–3.2 times higher conductivity and 1.4–2.3 times larger peeling strength than those of the commonly used carbon conductive agent added electrodes. Moreover, the flexible HFGR-400 ribbons with appropriate amount of functional groups ensure large contact area and strong interfacial interaction with Si particles, but without blocking the ion transport channels. Therefore, the HFGR-400 added Si electrode exhibits good cycle stability (2051.8 mAh/g after 200 cycles) and high rate performance. Moreover, the high Si mass loading HFGR-400 electrode shows a competitive areal capacity of 3.5 mAh cm−2 after 200 cycles, superior to most of the reported Si-based electrodes. Our work highlights the importance of conductive agents with high fractal-dimension structure for practical Si-based electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Fe/Cu-loaded needle coke particle electrode was prepared for 3DEF process. • Fe/Cu-NCPE has excellent stability, reusability, and EF-like catalytic performance. • The Fe-based oxide of the particle electrode is extracted from iron tailings. • Landfill leachate was treated effectively using 3DEF processing with Fe/Cu-NCPE. • The removal of COD, TN, and NH 3 -N reached 94.2%, 90.3%, and 93.8%, respectively. Landfill leachate is a typically difficult-to-degrade organic wastewater that, if not treated properly will cause serious harm to human health and the ecological environment. Three-dimensional electro-Fenton (3DEF) technology has received widespread attention because of its high mass transfer efficiency and current utilisation, and no secondary pollution. In this study, the Fe/Cu-loaded needle coke particle electrode (Fe/Cu-NCPE) was prepared, using which a 3DEF system was constructed with DSA as the anode and Ni/ACF as the cathode to treat mature landfill leachate. The optimal preparation conditions of the Fe/Cu-NCPE were obtained as Cu2+-modified needle coke: Fe-based oxides: binder = 32:8:15, particle size of 5 ± 0.5 mm, and Cu2+ loading of 3 %. The spectral analysis shows that the Fe/Cu-NCPE prepared in this study is a kind of particle electrode with superior performance and good stability. The optimum conditions for treating landfill leachate at an applied voltage of 9 V, an initial pH of 2, and a Fe/Cu-NCPE dosage of 25 g/L resulted in the removal of COD, colour, TN, and NH 3 -N of 94.2 %, 99 %, 90.3 %, and 93.8 %, respectively. In the 3DEF system for landfill leachate treatment, H 2 O 2 is generated at the cathode and polarized Fe/Cu-NCPE surface, which is activated by loaded Fe2+ and Cu+ in a Fenton(-like) reaction to produce •OH; Meanwhile active chlorine is generated by anodic electrocatalytic oxidation of Cl-. They attack humic acid and other organics in the wastewater as well as nitrogenous reductive substances to degrade them. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single/multi-step effluent treatment with BPS at supercritical conditions was performed. • HMs were recovered as NCH with BPS, with co-generation of H 2 -rich gas mixture. • The synergetic effect of HMs in wastewater catalyzes the gaseous yield during SCWG. • The synthesized NCH was employed for making carbon-based electrodes for lithium-sulfur batteries. Supercritical water gasification (SCWG) is an effective technique for the conversion of biomass into hydrogen-rich fuel gas. This work addresses two important aspects of the SCWG process by employing the concept of waste to wealth: first, the requirement of heterogeneous catalysts for better efficiency, and second, the safe disposal of byproducts of the process. Metal-contaminated aqueous effluent (Zn-EPW) is used as the reaction medium with the catalyst for single-step hydrothermal conversion of banana pseudo-stem (BPS) to synthesize multi-dimensional value-added products such as H 2 -rich fuel gas, nano metal–carbon hybrids (NCH), and treated aqueous phase. This study demonstrates the enhanced conversion of biomass into hydrogen-rich gas and recovery of heavy metals (HMs) in the form of nanometal carbon hybrids, which can be utilized to fabricate carbon-based electrodes in Li-S batteries. A comparative study of feedstock, such as a combination of Zn-EPW adsorbed on BPS (MA-BPS) with Millipore water, direct treatment Zn-EPW with BPS, and Millipore water with BPS (without HMs), was performed. The results inferred the catalytic effect of heavy metals increased the yield of hydrogen about ∼2.9 times with Zn-EPW and BPS and ∼1.7 times with MA-BPS and Millipore water over the non-catalytic operation. Furthermore, the obtained NCH were characterized to evaluate their performance for electrodes in energy storage devices. The electrochemical performance of NCH obtained after multi-step SCWG of MA-BPS with Millipore water and single-step treatment of Zn-EPW with BPS at 600 °C, have specific capacity of 610 and 615 mAh.g−1 at 0.1C respectively. [ABSTRACT FROM AUTHOR]

• This review presents an overview of the key techniques for optimizing crystal growth direction. • The structure–activity relationship between crystal orientation design and Na storage performance is discussed. • The prevalent challenges and new developments in regulating crystal orientation are given. Low-cost Na-ion batteries (NIBs) have manifested enormous potential for stationary energy storage and low-speed vehicles. Despite their potential advantages, the use of large and heavy Na+ ions as charge carriers in NIBs results in relatively slow kinetics and an inferior rate capacity. Moreover, Na+ de-intercalation is commonly accompanied by irreversible phase transition and sizeable volume changes, leading to structural degradation and capacity decay. Recent advancements have shown that tailoring the crystal growth direction and employing specific exposed crystal facets can bring about significant improvement in the electrochemical performance of electrode materials for NIBs. This review presents an overview of the key techniques for optimizing crystal growth direction, including surfactant addition, template-assisted synthesis, and foreign ion doping, followed by a detailed discussion pertaining to the corresponding regulatory mechanisms. Subsequently, the structure–activity relationship between crystal orientation design and Na storage performance is thoroughly examined with regards to the crystal anisotropy of cathode and anode materials. The prevalent challenges and new developments in regulating crystal orientation have been discussed given the development of high-performance NIB electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrochemistry of viologen on various heteroatom-doped GF has been investigated. • The surface of P-GF electrode is loaded with a conductive thin layer of carbon. • The P-GF electrode shows the highest conductivity and adsorption energy. • Viologen based AORFB with P-GF electrodes shows improved application performance. • Electrode with higher conductivity and adsorption energy is more beneficial to AORFB. In this paper, a series of heteroatom doping graphite felt electrodes are prepared by simple precursor impregnation and heat treatment, their application properties as electrode materials for viologen based aqueous organic redox flow batteries (AORFBs) are studied systematically. Elaborate physical, electrochemical characterization and density functional theory (DFT) calculation results indicate that the P-doped GF (P-GF) electrode with higher adsorption energy for viologen molecules, better conductivity and larger electrochemical reactive surface area exhibits better electrochemical performance towards viologen. The charge and discharge performance of the AORFBs with BTMAP-vi as anolyte and Nme-TEMPO as catholyte are investigated to verify the practical application performance of the P-GF electrode material. The AORFB with P-GF as electrodes shows lower polarization overpotential and higher discharge capacity at different current densities than that using pristine GF as electrodes. Specifically, the VE and EE of the BTMAP-vi/Nme-TEMPO AORFBs with P-GF as electrodes are 84.76 % and 82.85 % at the current density of 60 mA cm−2, 5.34 % and 6.18 % higher than that of the battery with GF as electrodes respectively. After 200 charge and discharge cycles, the capacity retention rate of the P-GF battery increases by more than 20 %, suggesting the better cycle stability. Besides, the peak power density of the P-GF battery achieves 120 mW cm−2, which is much higher than that of the GF battery (85 mW cm−2). The results of this work demonstrate that enhancing the conductivity and adsorption energy of the electrodes should be more effective to improve the performance of viologen based AORFBs, because the electrochemical reactivity of its active electrolytes has been excellent enough. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon layer combined with surface hydroxylation improve electrode PEC performance. • Carbon layer facilitate charge transport and prevent the corrosion of electrolyte. • Polarization electronic field formed via hydroxylation facilitate extraction of holes. • Surface hydroxylation promote redeposition of Fe active center in NiFe-LDH. • OH-BiVO 4 @C@NiFe-LDH photoanode exhibit excellent PEC activity and stability. Although great interest is focused on highly active photoanodes for efficient photoelectrochemical (PEC) water splitting, the issue on improving stability during oxygen evolution reaction (OER) is seldom discussed by far. Herein, a simple chemical way to construct carbon functional interlayer between bismuth vanadate (BiVO 4) and NiFe layered double hydroxide (NiFe-LDH) co-catalyst, combined with hydroxylation, can significantly improve the activity and stability. The enhanced electronic conductivity by carbon layer and formed strong polarization electronic field via surface hydroxylation, promote the interfacial charge transfer and bulk charge separation. More importantly, the carbon layer combined with more efficient redeposition of Fe active centers in NiFe-LDH catalysts caused by enhanced adsorption of Fe(III) onto Ni sites via hydroxylation, can greatly improve the OH-BiVO 4 @C@NiFe-LDH photoanode stability. With the synergistic effects of carbon functional interlayer and self-healing mechanism, OH-BiVO 4 @C@NiFe-LDH photoanode achieves extremely high photocurrent density (5.31 mA cm−2 at 1.23 versus the RHE), even maintaining more than 87.5 % of the initial photocurrent density within 20 h irradiation in KBi electrolyte with Fe(III) ions. This work provides a new strategy to enhance the performance of BiVO 4 –based photoanodes, especially for achieving long-term stability during OER. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eletrospun Fe N C fibers were used for an alkaline hydrazine fuel cell (AHFC). • Steam activation creates a hierarchical mesopore structure for oxygen reduction. • Steam activation raised the AHFC power density from 323 to 625 mW cm−2. • Fe 3 O 4 leaching by oxalic acid elevates the mesopore volume and hydrophobicity. • Oxalic acid leaching achieved 1240 mW cm−2 due to increased triple-phase boundary. In alkaline hydrazine fuel cells (AHFCs), the rapid kinetics of hydrazine oxidation contribute to their superior power density compared to other liquid fuel cells. However, the optimization of oxygen reduction reaction (ORR) electrodes in AHFCs has received limited attention, despite the potential importance of ORR as a rate-determining step. The wettability and pore structure of ORR catalysts are critical factors in facilitating reactant supply (O 2 and H 2 O) and improving catalyst utilization. In this study, we synthesized a hierarchical pore structure in a FeNC catalyst by excess iron incorporation and steam activation, and adjusted its water/oxygen gas contact property by oxalic acid treatment. The modified catalyst exhibited improved wettability and optimized triple-phase boundaries. Remarkably, utilizing a 25 cm2 electrode size and non-noble electrocatalysts, the resulting AHFC achieved a significant power density improvement from 630 to 1240 mW cm−2, setting a new record for AHFCs. This research highlights the importance of pore structure and surface engineering, including the role of excess iron, in enhancing the performance of ORR electrodes in AHFCs. [ABSTRACT FROM AUTHOR]

A scalable and facile polymer-blowing and galvanic replacement route for 3D porous carbon framework embedded with uniform Sb nanoparticles have been synthesized Such designed electrode architecture provides porous structure, high structure stabilities, high electronic conductivity and robust buffer layers, which could solve the issue of poor ionic and electronic transport in electrode materials and accommodate the large volume expansion. • 3D porous Sb ⊂ 3DPC was synthesized via a scalable and facile polymer-blowing and galvanic replacement route. • 3D porous Sb ⊂ 3DPC anode show superior rate capability and cycling performance. • Such 3D porous interconnected carbon-encapsulated structure enhances the electrochemical performance. The development of high-performance Na-ion batteries in order to meet the increasing demand of the industrial applications of energy storage requires low cost and large-scale preparation methods for battery electrodes with outstanding performance. In this work, we have designed a novel anode of three-dimensional porous interconnected carbon matrix embedded with Sb nanoparticles (Sb ⊂ 3DPC) via a scalable and facile polymer-blowing and galvanic replacement route. This designed electrode architecture provides large surface areas, large pore volumes and interconnected pore frameworks, supplying enlarged interface of the electrolyte and electrode, reducing the diffusion pathway and inhibiting the volume expansion of Sb during cyclic movement. The as-prepared Sb ⊂ 3DPC anode shows high Na-storage performance, such as an outstanding cycle stability (461 mA h g−1 at 100 mA g−1 over 200 cycles) and exceptional high rate capability (349 mA h g−1 at 5000 mA g−1). As for the application in the full Na-ion batteries, the assembled Sb ⊂ 3DPC//Na 3 V 2 (PO 4) 3 full cell also shows remarkable rate capability. Such polymer-blowing-based approach provides a low cost, uncomplicated and large scale preparation method for porous and stable electrode materials and opens up a wide horizon in other electrochemical applications. [ABSTRACT FROM AUTHOR]

A self-assembled mesoporous silica sphere templating process was developed to create hierarchical continuous porous coral reef like N-doped carbon nanostructures on stainless steel meshes as bifunctional electrodes for ultrahigh performance lithium ion based energy storage devices. The lithium ion capacitors (LICs) assembled from using the electrode as both the cathode and anode, exhibited a high energy density of 145 Wh kg−1 at a power density of 1.4 kW kg−1 and maintained an energy density of 58 Wh kg−1 under an ultrahigh power density of 27.3 kW kg−1, outperforming most of the state-of-the-art LICs. • Hierarchical porous N-doped carbon nanostructure on stainless steel mesh as anode. • Bifunctional electrodes for ultrahigh performance lithium ion batteries/capacitors. • Li ion capacitors deliver 145 Wh kg−1 at 1.4 kW kg−1 and 58 Wh kg−1 at 27.3 kW kg−1. • Excellent cycling stability with 85% capacity retention after 5000 cycle operations. A self-assembled mesoporous silica sphere templating process was developed to create hierarchical continuous porous coral reef like N-doped carbon nanostructures on stainless steel meshes as bifunctional electrodes for ultrahigh performance lithium ion based energy storage devices. The coral reef like carbon nanostructure achieved a high specific surface area of 1229 m2 g−1 and a large specific pore volume of 2.21 cm3 g−1, without application of chemical activations. The electrode, when serving as an anode for lithium ion batteries (LIB) or lithium ion capacitors (LIC), delivered an ultrahigh specific capacity of 2058 mAh g−1 at 0.2 A g−1. If used as a cathode for LICs, it generated a high specific capacity of 125 mAh g−1 at 0.1 A g−1. The LICs assembled from using the electrode as both the cathode and anode, exhibited a high energy density of 145 Wh kg−1 at a power density of 1.4 kW kg−1 and maintained an energy density of 58 Wh kg−1 under an ultrahigh power density of 27.3 kW kg−1, among the top tie of the state-of-the-art LICs. The cycling stability of the LIC was outstanding with a 85% capacity retention after 5000 cycle operations at 5 A g−1. The hierarchical continuous porous coral reef like N-doped carbonaceous nanostructure provides micropores as micro-reservoirs of Li ions for local and fast Li ion intercalation/de-intercalation, edge N-doping for additional redox pseudo-capacitances, and large pore volumes to accommodate the volume expansion/shrinkage at the charge/discharge cycles and to offer fast mass transfer path for electrolyte ions, altogether leading to the successful applications as bifunctional electrodes for Li ion based energy storage devices. [ABSTRACT FROM AUTHOR]