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[Display omitted] Flexible electrodes based on conversion-type materials have potential applications in low-cost and high-performance flexible sodium-ion batteries (FSIBs), owing to their high theoretical capacity and appropriate sodiation potential. However, they suffer from flexible electrodes with poor mechanical properties and sluggish reaction kinetics. In this study, freestanding CoS 2 nanoparticles coupled with graphene oxides and carbon nanotubes (CoS 2 /GO/CNTs) flexible films with robust and interconnected architectures were successfully synthesized. CoS 2 /GO/CNTs flexible film displays high electronic conductivity and superior mechanical properties (average tensile strength of 21.27 MPa and average toughness of 393.18 KJ m−3) owing to the defect bridge for electron transfer and the formation of the π–π interactions between CNTs and GO. In addition, the close contact between the CoS 2 nanoparticles and carbon networks enabled by the Co-N chemical bond prevents the self-aggregation of the CoS 2 nanoparticles. As a result, the CoS 2 /GO/CNTs flexible film delivered superior rate capability (213.5 mAh g−1 at 6 A g−1, better than most reported flexible anode) and long-term cycling stability. Moreover, the conversion reaction that occurred in the CoS 2 /GO/CNTs flexible film exhibited pseudocapacitive behavior. This study provides meaningful insights into the development of flexible electrodes with superior mechanical properties and electrochemical performance for energy storage. [ABSTRACT FROM AUTHOR]

Multifunctional nanocomposites with layered structures have shown great promise in supercapacitor (SC) applications due to their unique structures, abundant marginal active sites and diverse electrochemical reaction mechanisms. Using a facile chemical reduction method, a simple and efficient approach has been demonstrated for synthesising iron oxide-silver oxide/reduced graphene oxide (Fe3O4-Ag2O/rGO) nanocomposites. SEM images revealed that Ag2O/rGO nanocomposites showed noodle-like structure, and as the wt% of Ag grew, the connective network of grains increased from 105 to 190 nm. FETEM results indicated that the inter-planar spacings of 0.35 and 0.56 nm are identified for (331) and (220) crystalline planes of Fe3O4, respectively. ID/IG and IT/IG ratios varied between 0.81 and 1.45 and 0.7 to 6.57 for the Fe3O4-Ag2O/rGO nanocomposites. The bandgap initially increased from 2.16 to 3.5 eV and then decreased from 3.5 to 2.4 eV with the increase in wt% of Ag. The GCD curves showed that the specific capacitance varied from 237.42 to 787 F g− 1 for the Fe3O4-Ag2O/rGO nanocomposites. The maximum double layer capacitance 2.01 × 10− 9 F cm− 2 was observed for (Fe3O4)0.4-(Ag2O)0.6/rGO due to the interfacial reaction. The minimum Rct, Ecorr, and Icorr values are 154.72 Ω, 0.017 V and 1.61 µA, respectively, for 80 wt% Ag2O content of Fe3O4-Ag2O/rGO nanocomposite. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐based batteries have emerged as compelling candidates for grid‐scale energy storage, owing to their intrinsic safety, remarkable theoretical energy density and cost‐effectiveness. Nonetheless, the dendrite formation, side reactions, and corrosion on anode have overshadowed their practical applications. Herein, we present an in situ grown carbon network reinforcing Zn matrix anode prepared by powder metallurgy. This carbon network provides an uninterrupted internal electron transport pathway and optimize the surface electric field distribution, thereby enabling highly reversible Zn deposition. Consequently, symmetrical cells demonstrate impressive stability, running for over 880 h with a low voltage hysteresis (≈32 mV). Furthermore, this Zn matrix composite anode exhibits enhanced performance in both the aqueous Zn‐ion and the Zn‐air batteries. Notably, Zn//MnO2 cells display superior rate capabilities, while Zn‐air batteries deliver high power density and impressive Zn utilization rate (84.9 %). This work provides a new idea of powder metallurgy method for modified Zn anodes, showcasing potential for large‐scale production. [ABSTRACT FROM AUTHOR]

[Display omitted] The olivine lithium iron phosphate (LFP) cathode has gained significant utilization in commercial lithium-ion batteries (LIBs) with graphite anodes. However, the actual capacity and rate performance of LFP still require further enhancement when combined with high-capacity anodes, such as silicon (Si) anodes, to achieve high-energy LIBs. In this study, we introduce a gelatin-derived carbon network into a nanosized LFP cathode without the need for additional binding and conductive agents, employing a simple and cost-effective method. The resulting cathode exhibits an extremely high LFP content (∼92.3 wt%), enabling it to show a high real capacity of 159.7 mAh/g at 0.2 C in half cells. Additionally, the interconnected carbon network effectively facilitates electron and Li+ transport, providing rapid pathways within the LFP nanoparticles. Consequently, the cathode exhibits superior rate capability (107.3 mAh/g at 10 C) and good cycling performance (with a capacity retention of ∼ 80 % after 500 cycles). To further assess its practical viability, the LFP cathode is assembled into a full cell utilizing a Si-based anode with a N/P ratio of 1.1. The resulting full cell delivers a significantly high energy density of 419.7 Wh kg−1, coupled with prolonged cycle life, highlighting its promising prospects for practical applications. [ABSTRACT FROM AUTHOR]

Cathode active materials and conductive additives for thermal batteries operating at high temperatures have attracted research interest, with a particular focus on compounds offering high thermal stability. Recently, FeF3 has been proposed as a candidate for high-voltage cathode materials; however, its commercialization is hindered by its low conductivity. In this study, conductive additives, such as Ni-coated carbon composites (multi-walled carbon nanotubes (MWCNTs) and carbon black (CB)), were utilized to enhance the thermal stability and conductivity of FeF3. The incorporation of metal–carbon conductive additives in the FeF3 composite increased the thermal stability by more than 10 wt.% and ensured high capacity upon conductivity enhancement. The FeF3@Ni/MWCB 15 wt.% composite containing 30 wt.% Ni exhibited a discharge capacity of ∼86% of the theoretical capacity of 712 mAh/g. The use of Ni-coated carbon-based conductive additives will allow the application of FeF3 as an effective high-temperature cathode material for thermal batteries. [ABSTRACT FROM AUTHOR]

Na3V2(PO4)3/C powders were prepared by using various amounts of surfactant additives such as cetyltrimethylammonium bromide (CTAB), polyvinyl pyrrolidine (PVP), and mixed CTAB-citric acid. The structural, microstructural, and electrochemical properties were analyzed by various characterization methods such as X-ray diffractometry, electron microscopy, cyclic voltammetry, and galvanostatic charge and discharge techniques. Single-phase Na3V2(PO4)3 (NVP) with rhombohedral crystal structure was obtained for all organic additives by calcination at 850 °C for 6 h in an Ar/10 vol.% H2 atmosphere. The rather large NVP particles (~ 300–500 nm) were dispersed on a continuous 3D carbon network which was in situ generated by burning the organic additives. However, the NVP powders prepared by PVP surfactant had the bulky morphology with a plenty of pores. Among the organic additives, the mixed CTAB-citric acid additive showed the better electrochemical properties including high capability rate (104 mAh g−1 @1C) and high cycling performance (capacity retention of 97.5%). [ABSTRACT FROM AUTHOR]

Silicon (Si) anode materials have received much attention on account of their unparalleled theoretical specific capacity, but they suffer from huge volumetric expansion and particle pulverization, which leads to rapid capacity fading and poor electrical conductivity as well. In this work, a quaternary silicon/carbon (Si/C) composite anode material is proposed which combines the advantages of both graphene and the three-dimensional carbon framework through rational structural design and simple synthesis methods. Nanosilicon/carbon nanofibers/pyrolytic carbon (SCC) composite particles are first synthesized by spray drying and pyrolysis, which are then wrapped by graphene nanosheets through a second spray drying and pyrolysis process to obtain the final product (SGCC). In this composite, a 3D carbon skeleton composed of carbon nanofibers and pyrolytic carbon serves as an electric conductive matrix that supports and stabilizes Si nanoparticles, while graphene nanosheets wrapped on the surface further improve the conductivity and structure stability of the composite particles, and isolate the particles from direct contact with electrolytes. Meanwhile, the rich pores of the composite particles can effectively provide space for the volume expansion of Si during lithiation. As a consequence, the as-prepared SGCC composite shows a high initial Coulomb efficiency of 84.7%, a high reversible capacity of 2150.8 mA h g–1, and a good capacity retention rate of 83.75% after 100 cycles. [ABSTRACT FROM AUTHOR]

Transition metal oxides with various valence states have high specific capacitance and have attracted much attention. However, the poor cycle stability caused by material agglomeration seriously limits the play of its high activity. Herein, we create a stress dispersion structure (CuxO composite porous carbon net) by in situ lyophilization and one-step carbonization, effectively anchoring highly reactive copper oxides and highly conductive carbon networks combined with high nitrogen doping of 10.7%, to investigate their electrochemical performance in supercapacitors. Specifically, the specific capacitance of CuxO@NPC can be as high as 392 F/g (0.5 A/g) in the three-electrode system with 6 mol/L KOH as electrolyte. When applied to the two-electrode system, the cycle stability of the whole device can reach 97% after 10,000 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] Cobalt selenide, as a star material in battery industry, has attracted much attention. However, when it is applied solely in sodium ion batteries, it will cause large volume expansion and material agglomeration, which will seriously affect the overall performance of batteries. In this work, we use ice bath impregnation to combine CoSe 2 nanoparticles with porous nitrogen-doped carbon networks (NC) as advanced anodes for ultra-long cycle life sodium ion batteries (SIBs). CoSe 2 nanoparticles are evenly attached to NC with strong interfacial contacts in CoSe 2 @NC. The strong contact of CoSe 2 on the porous carbon network, along with the carbon network's unique network cross-linking structure, results in rapid electron transfer and Na ion diffusion kinetics of CoSe 2 @NC, resulting in superior electrochemical performance. Besides, we have synthesized CoSe 2 @NC with different loading by changing Co2+ concentration. The results show that CoSe 2 @NC anode thus provides a high reversible capacity of 406 mAh/g. In addition, at high current 5 A/g, it can keep a reversible capacity of 300 mAh/g after 4500 cycles with an average capacity loss of less than 0.01 % per cycle. The excellent anchoring structure enables it to form stable solid electrolyte film (SEI) and reduce the amount of dead sodium in the first charge–discharge process, showing high Initial Coulombic Efficiency (ICE) (89.2 %). Finally, CoSe 2 @NC and Na 3 V 2 (PO 4) 3 (NVP) are assembled into a full cell and the results shows an ultra-long cycle stability at 0.1 A/g. This strategy will facilitate the application of transition metal selenides in next-generation energy storage systems. [ABSTRACT FROM AUTHOR]

Capacitive deionization (CDI) technology, based on the electric field ion capture mechanism, holds significant application prospects for purifying copper ions (Cu2+) from industrial wastewater. The development of electrode materials is crucial for enhancing capacitive Cu2+ removal. Herein, the three-dimensional nanoporous carbon network is prepared from agricultural waste rice husk using basic zinc carbonate as the pyrolytic activator. It is found that the ZnO site-occupying effect, stemming from the pyrolysis activator, exerts a pronounced regulatory influence on the porous structure of carbon network. The carbon electrode exhibits a satisfactory specific capacitance of 256.2 F g−1 at 0.5 A g−1. More importantly, the assembled symmetrical CDI cell demonstrates an excellent electrochemical adsorption capacity of 60.5 mg g−1 for Cu2+. Such exceptional capacitive deionization performance can be attributed to the synergistic effect of the electrochemical double-layer and electrochemical reduction during the adsorption process of Cu2+. Thus, this research offers a promising strategy for efficient wastewater treatment. [Display omitted] • ZnO site-occupying effect on pore formation has been thoroughly investigated. • The CDI cell presents a superb Cu2+ adsorption capacity of 60.5 mg g−1. • The electrochemical synergistic effect enhances the ability to purify Cu2+. [ABSTRACT FROM AUTHOR]

As an important part of lithium-sulfur battery (LSB), separator not only provides ion transport channel but also plays a key role in ensuring battery safety. However, the aperture of the commercial separator polypropylene (PP) is relatively large, which cannot effectively inhibit the migration of polysulfides generated during the charging and discharging process between the positive and negative electrodes, resulting in a decrease in the cycle stability of LSB. In this work, a modified LSB separator Ni 3 S 2 -NiO@AC-4@PP is designed, which is anchored by Ni 3 S 2 -NiO heterojunction on volcanic rock-like three-dimensional porous carbon network (AC) as the functional interlayer. The AC possesses a large specific surface area and excellent electrical conductivity, creating sufficient space for the physical and chemical adsorption of insoluble polysulfides. The Ni 3 S 2 -NiO heterojunction is embedded and attached to the AC, which helps to hinder the diffusion of polysulfides and accelerate the redox reaction. It is also confirmed by density functional theory (DFT) calculation that Ni 3 S 2 -NiO heterojunction inhibited the shuttle of polysulfides through the adsorption capacity of NiO and the catalytic activity of Ni 3 S 2. Thus, the Ni 3 S 2 -NiO@AC-4@PP battery exhibits an elevated initial specific capacity of 1027.8 mAh g−1 at 0.2C, maintaining long-term stability after 200 cycles with the capacity retention rate of 81.4 %. At the higher current density (2C), Ni 3 S 2 -NiO@AC@PP battery demonstrates durable cycle with the capacity retention rate of 91.3 %. This study proposes a new feasible strategy to obtain high-performance, low-cost modified separators by designing functional interlayers with excellent adsorption and catalytic properties. This work constructs a functional interlayer Ni 3 S 2 -NiO@AC modified lithium-sulfur battery separator by utilizing Ni 3 S 2 -NiO heterojunction and three-dimensional porous carbon network AC, which not only significantly promotes the transformation of polysulfides, but also provides a innovative tactics for constructing functional separator to raise the battery efficiency of LSBs. [Display omitted] • Volcanic rock-like functional interlayer Ni 3 S 2 -NiO@AC nanomaterial was prepared. • Synergistic effect of Ni 3 S 2 -NiO heterojunction and AC improves LSB performance. • Ni 3 S 2 -NiO@AC-4@PP battery exhibits excellent cycle stability. [ABSTRACT FROM AUTHOR]

Cathode active materials and conductive additives for thermal batteries operating at high temperatures have attracted research interest, with a particular focus on compounds offering high thermal stability. Recently, FeF3 has been proposed as a candidate for high-voltage cathode materials; however, its commercialization is hindered by its low conductivity. In this study, conductive additives, such as Ni-coated carbon composites (multi-walled carbon nanotubes (MWCNTs) and carbon black (CB)), were utilized to enhance the thermal stability and conductivity of FeF3. The incorporation of metal–carbon conductive additives in the FeF3 composite increased the thermal stability by more than 10 wt.% and ensured high capacity upon conductivity enhancement. The FeF3@Ni/MWCB 15 wt.% composite containing 30 wt.% Ni exhibited a discharge capacity of ∼86% of the theoretical capacity of 712 mAh/g. The use of Ni-coated carbon-based conductive additives will allow the application of FeF3 as an effective high-temperature cathode material for thermal batteries.

10%-γGCMO was successfully prepared based on mechanical stress preparation of γ-GY. The formation of S-scheme heterojunctions at the interface accelerated the migration between catalysts and enhanced the redox ability of 10%-γGCMO. The heterojunction type between γ-GY and CuMoO 4 was determined as S-scheme heterojunction as well as the electron migration path between the catalysts base on in situ radiation XPS spectroscopy and Density Functional Theory (DFT) as the theoretical guidance. [Display omitted] • γ-GY was successfully prepared by mechanical stress. • γ-GY/CuMoO 4 S-scheme heterojunction was constructed. • The 10%-γGCMO shows excellent photocatalytic hydrogen evolution activity. • In situ radiation XPS spectrum and density functional theory (DFT) were used as theoretical guidance. The introduction of novel materials is crucial to broaden the development of the field of artificial photosynthesis. The high recombination rate of photogenerated carriers remains one of the fundamental reasons that hinder the development of photocatalysis. In view of this, we coupled γ-GY containing alkyne bonds with CuMoO 4 to form interfacial S-scheme heterojunctions. The formation of S-scheme heterojunctions accelerates the electron transfer and improves the separation efficiency of photogenerated carriers, while enhancing the photoreduction ability of the composite catalysts and allowing more electrons to participate in the reduction reaction of H+ under light conditions. The heterojunction type between γ-GY and CuMoO 4 was determined as S-scheme heterojunction as well as the electron migration path between the catalysts base on in situ radiation XPS spectroscopy and Density Functional Theory (DFT) as the theoretical guidance. This work provides a basis for the structural optimization of γ-GY based on in situ and theoretical calculations, and expands the application of mechanical preparation of γ-GY in photocatalysis. [ABSTRACT FROM AUTHOR]

Transition metal oxides with various valence states have high specific capacitance and have attracted much attention. However, the poor cycle stability caused by material agglomeration seriously limits the play of its high activity. Herein, we create a stress dispersion structure (CuxO composite porous carbon net) by in situ lyophilization and one-step carbonization, effectively anchoring highly reactive copper oxides and highly conductive carbon networks combined with high nitrogen doping of 10.7%, to investigate their electrochemical performance in supercapacitors. Specifically, the specific capacitance of CuxO@NPC can be as high as 392 F/g (0.5 A/g) in the three-electrode system with 6 mol/L KOH as electrolyte. When applied to the two-electrode system, the cycle stability of the whole device can reach 97% after 10,000 cycles.

Performance of polyaniline was dramatically enhanced by engineering robust PANI/carbon interfaces, and a proton supercapacitor with high energy/power densities was further demonstrated based on the prepared PANI cathode and an h-WO 3 anode. [Display omitted] Supercapacitors are high power energy storage devices, however, their application are remain limited by the low energy density. Developing high capacity electrode materials and constructing devices with high operating voltage are effective ways to solve this problem. Herein, performance of polyaniline (PANI) electrode materials is dramatically enhanced by engineering robust PANI/carbon interfaces, through assembling PANI nanorod array on rose petals derived carbon network (RPDCN). The structure of the PANI is optimized by adjusting the concentration of the aniline precursor. The unique structure enables the prepared PANI/RPDCN composite show a high capacitance of 636 F g−1 at 0.5 A g−1, based on the total weight of PANI and RPDCN substrate. The robust interface effectively prolonged the composite electrode stably cycled for over 2000 cycles at 2 A g−1 with a capacity retention of 89%. When coupled with a hexagonal tungsten oxide (h-WO 3) anode, a high-power asymmetric proton supercapacitor with high energy densities (29.0 Wh kg−1/0.61 kW kg−1 and 21.4 Wh kg−1/19.51 kW kg−1) was assembled. This work provides an effective and eco-friendly route toward superior PANI electrodes and proposes a promising high-power energy storage system using proton as working ion. [ABSTRACT FROM AUTHOR]

A three-dimensional MnO/C nanocomposite is fabricated through a simple route of immersion and subsequent calcination. The carbon content and morphology of the sample are adjusted by adjusting the calcination temperature. This material combines the excellent lithium storage performance of MnO and the good stability of carbon. Because MnO is embedded in the three-dimensional carbon networks, it can provide proper space to alleviate the volume effect during discharging and charging. The unique architecture and large surface area enable the composites to exhibit remarkable lithium storage properties with outstanding rate performance, high reversible capacity, and cycle life. The optimized sample (MnO/C-750) has excellent performance of 1067.95 mAh g−1 at 0.2 A g−1 over 200 cycles and 722.32 mAh g−1 at 1 A g−1 over 600 cycles.

Geometric structures of carbon networks are key in designing their material properties. In particular, optimization of curved structures through the introduction of topological defects and doping of heteroatoms in the lattice is crucial to the design of carbon-based, non-noble-metal-free catalysts. A simple and practical mathematical model based on discrete geometric analysis is proposed to describe the geometric features of carbon networks and their relationships to their material properties. This model can pre-screen candidates for novel material design, and these candidates can be further examined by the density functional theory (DFT). Inspired by observations regarding the preferential doping of heteroatoms at local curved sites, the important characteristics of the candidate material were experimentally realized, and its enhanced catalytic activity facilitated by chemical dopants was confirmed in the designed carbon network. [Display omitted] • Optimization of curved structures crucial to design novel carbon-based materials. • Explore links amid Gauss curvatures and catalytic properties of 3D curved graphene. • Heteroatoms prefer to be doped at local curved sites. • Important characteristics of the candidate material were experimentally realized. • Enhanced catalytic activity by chemical dopants in the designed carbon network. [ABSTRACT FROM AUTHOR]

[Display omitted] • A wire-in-tube Co 9 S 8 /C@C composite is constructed to realize fast and stable potassium storage performance. • The rate capability of WIT Co 9 S 8 /C@C composite outperforms most cobalt sulfide-based anodes reported so far for PIBs. • The internal carbon network engineering of WIT structure results in superior structural integrity and fast charge transportation. Hollow structured composites show great promising to accommodate the large volume fluctuation of high-capacity anodes with good structure integrity, while it still suffers from insufficient charge transportation due to the intrinsic low conductivity of anodes and the limited transport channels within hollow structure. Herein, conductive carbon networks are rationally constructed within hollow structure to realize both excellent structure stability and superior charge transportation. By encapsulating MOF-derived Co 9 S 8 /C wires into hollow carbon tubes, as-prepared wire-in-tube (WIT) Co 9 S 8/ /C@C composite manifests exceptional potassium storage performance. It displays excellent cycling retention and maintains high capacities of 410 mA h g−1 at 100th cycle under 0.1 A/g and 201 mA h g−1 after 1500 cycles at 1 A/g. It also achieves a superior rate capability of 200 mA h g−1 at 10 A/g, surpassing most cobalt sulfide-based anodes that have been reported for PIBs. As revealed by in-depth characterizations and theoretical calculation, the conductive network engineering within hollow structure can optimally augment the electron/ion conductivity of Co 9 S 8 and tolerate its volume changes during cycles, thus leading to the exceptional performance of WIT Co 9 S 8/ /C@C composite. [ABSTRACT FROM AUTHOR]

Realization of highly efficient sulfur electrochemistry, as well as the high capacity of lithium–sulfur (Li–S) batteries, can be achieved by the scientific construction of electrode host materials. In this study, using molten NaCl, a 3D porous nitrogen‐doped carbon with uniformly embedded Co atom clusters (Co/PNC) is developed by pyrolyzing the precursors with NaCl at high temperatures. In the composite structure, a network carbon skeleton containing hierarchical pores acts as an advanced matrix for sulfur electrodes, and the doping of N and Co is subject to inhibit the shuttle of long‐chain lithium polysulfides through chemical adsorption. The Co/PNC, with the optimized amount of Co, delivers an initial specific capacity of 1105.4 mAh g−1 at 0.2 C with a capacity drop of only 0.064% after the cell is charged and discharged for 300 cycles at 1 C, revealing its potential in promoting the large‐scale application of Li–S batteries. [ABSTRACT FROM AUTHOR]

Sufficient and well-distributed active sites and highly conductive carbon matrix are two important factors to achieve highly efficient electrocatalysts. In this study, we report an adjusted metal-organic frameworks (MOF)-based route for the preparation of nitrogen-doped Fe/Co bimetallic electrocatalysts. With suitable Fe/Co molar ratio (Fe/Co = 1/4.15), Co nanoparticles (NPs) with mild oxidation state and Co 3 Fe 7 alloys wrapped with thin graphene layers are embedded in an integrated and continuous carbon network. The corresponding FC@NCs-4.15 catalyst exhibits excellent oxygen reduction reaction (ORR) activity (onset potential (E onset) of 0.94 V and half-wave potential (E 1/2) of 0.84 V vs RHE) in alkaline medium, close to commercial Pt/C and superior to the other two FC@NCs. The desirable ORR performance results from the uniform distribution Co 3 Fe 7 active sites, electron density modification from Co NPs to surrounding carbon layers, hierarchical pore structure with large surface area, low carbon content, high pyridinic and graphitic N components. The FC@NCs-4.15 also displays satisfactory methanol crossover tolerance and durability. [ABSTRACT FROM AUTHOR]

Silicon-based materials with designed morphology and composite structure have received increasing interest in recent years due to the potential wide application for energy storage devices. However, these Si-based nanocomposites were usually synthesized and functionalized with other materials at a high temperature. Herein, one flocculent carbon network-twined C/Si/SiC nanocomposites were synthesized by a novel in-situ laser irradiation method using SiC targets as both a template and the source of C and Si. The fragmentation, decomposition and reshaping processes of bulk SiC to flocculent C/Si/SiC are simultaneously accomplished in one step, which can provide a more stable structure between epitaxial Si layer and C layer. What is more, due to the distinct laser-induced loose microstructure and flocculated carbon nanosheets, such nanocomposites exhibit a high specific surface area and hierarchically porous structure. Image 1 • Flocculent carbon network-twined C/Si/SiC composite structure was synthesized. • Bulk SiC were changed to flocculent carbon network-twined C/Si/SiC. • The composites were fabricated by simple in-situ laser irradiation in nature. • Such unique flocculent network structures exhibit a high specific surface area. [ABSTRACT FROM AUTHOR]

Abstract A facile carbothermal route was adopted to obtain niobium carbide nanoparticles (NPs) embedded in carbon network from Nb2O5 to study photocatalytic behavior. Optimization of synthesis parameters to obtain single phase NbC NPs has been successfully done. The phase identification, morphology and nature of carbon were determined with the help of X-ray diffraction, transmission electron microscopy (TEM) and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) suggested the presence of multiple oxidation states of Nb associated to NbC and NbCxOy centers on the surface of NPs. Due to the presence of NbCxOy on the surface of NPs, absorption under visible region of EM spectrum has been observed by UV-visible spectroscopy. Different organic dyes (RhB, MB and MO) were used to study the effect of holding time on the photocatalytic performance of as-synthesized samples. RhB dye was found to be the most sensitive organic molecule among all the considered dyes and degraded 78% in 120 min.

LiFePO4 (LFP) has been recommended as a promising cathode material due to its excellent cycle performance and high safety. However, the poor performance of low temperatures restricts the development and application of LFP cathode. Herein, the electrochemical properties of the previously synthesized LFP/C-P composite with carbon coating and phosphorus doping are discussed in the low temperature. In the low-temperature environment of − 40 °C, the first discharge-specific capacity of the LFP/C-P composite cathode at 0.1 C can reach 82.7 mAh g−1, while discharge-specific capacity of pristine commercial LFP is only 72.2 mAh g−1. To further improve the electrochemical performance of LFP/C-P at low temperatures, different charging-discharging methods were compared. It is noted that prolonging the constant voltage charging time can further improve the electrochemical performance of the cell, which increases the discharge capacity of LFP/C-P to 85.8 mAh g−1. The LFP/C-P composite cathode therefore not only ameliorates the poor electrochemical performance of LFP but provides a new way to broaden its application range. [ABSTRACT FROM AUTHOR]

Cost-effective electrocatalysts with excellent oxygen reduction reaction (ORR) activity are requisite for the commercial application fuel cells and zinc-air batteries. Herein, we prepare a series of carbon-based non-precious metal catalysts by simply carbonizing the mixture of FeCo-ZIF, melamine and soya-bean oil. The microstructure and electrochemical activity of the prepared catalysts highly depend on the adding amount of FeCo-ZIF. With proper addition, the FeCo-ZIF are transformed into Co 5.47 N and Co 0.72 Fe 0.28 alloy nanoparticles, which are embedded in the in situ formed carbon network consisted of nitrogen-doped graphene-like carbon nanosheets and interwoven carbon nanotubes. The resulted catalyst (FeCo@NCs-0.15) with considerable specific surface area and high pore volume demonstrates a superior ORR catalytic activity than commercial Pt/C with a half-wave potential (E 1/2) of 0.83 V (vs. RHE), onset potential (E onset) of 0.97 V (vs. RHE) and 4-electron dominated reaction path. The durability and methanol resistance are also better than that of commercial Pt/C in alkaline solution. This study provides an inexpensive, facile and scalable strategy to simultaneously realize non-precious metal-based active sites, nitrogen-doping, porosity and highly conductive carbon matrix in one electrocatalyst by one step. [ABSTRACT FROM AUTHOR]

TiO2, with low cost, highly environmental benignity, and high safety, has been considered to exhibit great potential as an advanced anode material for sodium ion batteries (SIBs), although slow electron/ion transport hinders its development. Here, we find the composite of thin‐walled TiO2 nanotubes with a double carbon coating by hydrothermal reaction and calcination, which effectively improves the structural stability and promotes electron transport. The composite material of TiO2/rGO@NC delivers the first charge specific capacity of 245.8 mA h g−1 at 0.02 A g−1, along with 118.7 and 91.7 mA h g−1 at high current densities of 2.5 and 5 A g−1. Simultaneously, it can still offer 135.8 mA h g−1 over 500 cycles at the current density of 1 A g−1. The remarkable electrochemical performance, combining with its own properties, demonstrates that it can be used as a hopeful anode material for superior performance SIBs. [ABSTRACT FROM AUTHOR]

Low Coulombic efficiency (CE) and safety issues are huge problems that hinder the practical application of Li metal anodes. Constructing Li host structures decorated with functional species can restrain the growth of Li dendrites and alleviate the great volume change. Here, a 3D porous carbonaceous skeleton modified with rich lithiophilic groups (Zn, ZnO, and Zn(CN) 2 ) is synthesized as a Li host via one-step carbonization of a triazole-containing metal-organic framework. The nano lithiophilic groups serve as preferred sites for Li nucleation and growth, regulating a uniform Li + flux and uniform current density distribution. In addition, the 3D porous network functions as a Li reservoir that provides rich internal space to store Li, thus alleviating the volumetric expansion during Li plating/stripping process. Thanks to these component and structural merits, an ultra-low overpotential for Li deposition is achieved, together with high CE of over 99.5% for more than 500 cycles at 1 mA cm -2 and 1 mAh cm -2 in half cells. The symmetric cells exhibit a prolonged cycling of 900 h at 1 mA cm -2 . The full cells by coupling Zn/ZnO/Zn(CN) 2 @C-Li anode with LiFePO 4 cathode deliver a high capacity retention of 94.3% after 200 cycles at 1 C., (© 2023 Wiley-VCH GmbH.)

Recently, lithium-ion batteries (LIBs) have been considered as an extremely important energy source for abundant smart electronic devices. Even so, lower cycle life of LIBs and capacitance performance remains rough challenges due to dramatic structure degradation. Rational structure design is highly desirable to fully improve the electrochemical performance of LIBs. Herein, a hybrid structure of carbon network adorned with nickel particles (Ni/CN) was developed. The ultra-thin interconnected CNs not only provide robust support for ultra-tiny Ni nanoparticles, but also enhance the electrical conductivity network of hybrid structure. The carbon around the Ni nanoparticles is graphitized as soft carbon with large interlayer spacing and good electrical conductivity, which benefits Li+ ion insertion/extraction. Furthermore, large specific surface area, open internal space are favorable for shorten Li+ ion diffusion channel and rapid charge transfer are favorable for accelerating Li+ ion diffusion and accommodating volume strain during the repeated lithiation/delithiation process. Benefiting from these structural and compositional advantages, the Ni/CN anode displays an ultra-stable cyclic lifespan with a specific capacity of 544.7 mAh g−1 (at 1 A g−1) even after 2000 cycles, excellent capacity retention of 121.1%. Therefore, high-energy storage and long lifespan of Ni/CN materials display a bright prospect. Image 1 The as-fabricated Ni/CN exhibits distinctive structure and possible mechanism for lithium ion storage. • We designed a 3D carbon network structure decorated with nickel nanoparticles. • Synergistic effect between nickel and carbon network improves capacity and stability. • It presents an ultrahigh cyclic duration (121.1% retention after 2000 cycles). [ABSTRACT FROM AUTHOR]

Through this work, a carbon network/aluminum matrix porous composite material was analyzed for its susceptibility to material degradation in sulfuric acid and seawater corrosive media. Simple potentiodynamic electrochemical testing was implemented, and from polarization curves, the Tafel coefficients and exchange current densities were obtained for a comparative analysis. The pseudo exchange current densities for corrosion of the composite material were compared to those found for Al 1235 and 6061-T6. By relating the pseudo icorr of these materials in each environment, an understanding regarding the relative propensity to corrosion was determined. According to the recovered data, the composite had the lowest pseudo icorr in all corrosion systems and was consequently inferred the least likely to corrode. The factor that primarily contests this conclusion is the material's relatively large exposed surface area. The existence of carbon along the grain boundaries in the C/Al composite improved its corrosion behavior. Further discussion concerning the implication of βc is offered. Electrochemical impedance spectroscopic (EIS) tests were performed in the frequency range from 0.001 Hz to 100 kHz. An immersion corrosion test was conducted to calculate the corrosion rate in different environments. Morphological observation on the corrosion surface was also carried out to evaluate the corrosion product deposition on each material. [ABSTRACT FROM AUTHOR]

Abstract SnO 2 monocrystals with an average particle size of ∼10 nm have been in-situ embedded in a tridimensional carbon network (marked as SnO 2 @C) with a high loading percentage of 39.5 wt%. The synthetic mechanism of SnO 2 @C nanocomposite is discussed. The X-ray photoelectron spectroscopies demonstrate probable chemical bonding between SnO 2 nanoparticles and the carbon framework for enhanced lithium storage performance of SnO 2 @C nanocomposite as an anode material for lithium ion batteries. The SnO 2 @C anode material delivers an initial charge capacity of 844 mAh/g at 0.1 C, and can retain a specific capacity of 661 mAh/g after 700 electrochemical cycles at 1 C (1 C = 0.79 A/g), showing considerably improved cycling and high-rate performance as compared with the bare SnO 2 material. The high lithium storage capacity of SnO 2 @C anode material can be attributed to electrochemical reversibility related to the reduction of SnO to Sn and corresponding re-oxidation process, according to a reversible redox pair at 1.10/1.25 V recorded in CV cycles. The SnO 2 @C anode also reveals outstanding cycling stability at elevated temperature, resulting in a remaining capacity of 512 mAh/g after 125 cycles at 1 C and 233 mAh/g after 300 cycles at 5 C at 55 °C, respectively. TEM/HRTEM images show desirable structural integrity of cycled SnO 2 @C nanocomposite and the robustness of the carbon network, which significantly contributes to superior lithium storage performance. Graphical abstract Image 1 Highlights • SnO 2 monocrystals are in-situ embedded in a tridimensional carbon network. • SnO 2 @C nanocomposite delivers superior lithium storage performance at 55 °C. • Chemical bonding is introduced between SnO 2 nanoparticles and the carbon network. • TEM images demonstrate preserved nanostructure of cycled SnO 2 @C nanocomposite. [ABSTRACT FROM AUTHOR]

Abstract Li 2 MnSiO 4 is considered as a promising cathode candidate for high energy density Lithium-ion batteries (LIBs), due to its high theoretical capacity, favorable working potential as well as the low-cost and non-toxic nature of manganese element. However, it suffers from low capacity utilization and inferior cycling performance, due to the structural rearrangement upon cycling, phase impurities and manganese dissolution. To address these issues, nanostructure construction and carbon coating proves to be effective approach. In this work, we introduce an in situ template synthesis of a phase-pure Li 2 MnSiO 4 @C (MP-LMS@C) composite, which exhibits unique mesoporous morphology with nanosized Li 2 MnSiO 4 granules homogenously encapsulated in the interconnected carbon networks. Such unique Li 2 MnSiO 4 @C structure not only facilitates electron conduction and Li+ transport, but also suppresses the manganese dissolution, as a result, the mesoporous Li 2 MnSiO 4 @C cathode exhibits greatly improved electrochemical performance, with a high specific capacity of 230 mAh g−1, good rate capability and superior capacity retention of 81% over 100 cycles. [ABSTRACT FROM AUTHOR]

The utilization of ionic liquids as electrolyte is beneficial for realization of high energy density supercapacitors due to their high operation voltage. Nevertheless, ionic liquids electrolytes suffer from sluggish ion diffusion and poor wetting behavior on porous electrodes as a result of large ion sizes and high viscosity, which has severely hindered their practical use. Herein, highly sp 2 hybridized and nitrogen, oxygen dual-doped nanoporous carbon networks were prepared based on charge-induced self-assembly strategy using chitosan as carbon precursor with reduced graphene oxide (GO) in between as conductive scaffolds. The optimized material as supercapacitor electrodes exhibits an outstanding specific capacitance of 201 F g −1 in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4 ) electrolyte at 0.5 A g −1 with a maximum energy density of 111 Wh kg −1 , superior to numerous reported values, which are attributed to multiple synergistic effects of several beneficial characteristics, that is, excellent conductivity deduced from highly sp 2 hybridized carbon originated from carbonized chitosan and graphene conductive scaffolds being in favor of rate performance and cyclic stability, nitrogen and oxygen functionalization improving the surface wettability with electrolyte as well as contributing to the capacitance, large specific surface areas providing abundant active sites to boost charge capacity, and sheet-like structures effectively shortening diffusion pathways to improve ion transports. [ABSTRACT FROM AUTHOR]

Lithium iron silicate has caught tremendous attentions as an appealing cathode for future lithium-ion batteries due to high capacity, low cost, and environmental friendliness, and its drawback of extremely low conductivity can be overcome efficiently through nanoarchitecture building. However, the construction of nanostructures always involves with expensive surfactants and complicated synthetic processes, which restrict these methods from large-scale production. In this paper, we develop a simple synthetic route to prepare hierarchical porous Li2FeSiO4/C. XRD, SEM, TEM, Raman, and N2 adsorption-desorption are employed to investigate its physical properties. Electrochemical tests reveal that the composite delivers a high specific capacity of 243.5 mAh g−1, superior rate capability, and excellent cycling performance with capacity retention of 95.2% after 200 cycles. The excellent electrochemical performance should be attributed to the unique structure in which hierarchical pores provides fast transport channels for lithium ions and interconnected carbon coating builds up conductive networks to enhance the conductivity of Li2FeSiO4. In addition, electrochemical impedance spectroscopy, ex situ SEM, and TEM are conducted to demonstrate its structural stability upon long-term cycling. In addition, the route described in this work is facile, cheap, and easily scaled-up, which allows for extension to the fabrication of other energy storage materials. [ABSTRACT FROM AUTHOR]

Through this work, a carbon network/aluminum matrix porous composite material was analyzed for its susceptibility to material degradation in sulfuric acid and seawater corrosive media. Simple potentiodynamic electrochemical testing was implemented, and from polarization curves, the Tafel coefficients and exchange current densities were obtained for a comparative analysis. The pseudo exchange current densities for corrosion of the composite material were compared to those found for Al 1235 and 6061-T6. By relating the pseudo icorr of these materials in each environment, an understanding regarding the relative propensity to corrosion was determined. According to the recovered data, the composite had the lowest pseudo icorr in all corrosion systems and was consequently inferred the least likely to corrode. The factor that primarily contests this conclusion is the material’s relatively large exposed surface area. The existence of carbon along the grain boundaries in the C/Al composite improved its corrosion behavior. Further discussion concerning the implication of βc is offered. Electrochemical impedance spectroscopic (EIS) tests were performed in the frequency range from 0.001 Hz to 100 kHz. An immersion corrosion test was conducted to calculate the corrosion rate in different environments. Morphological observation on the corrosion surface was also carried out to evaluate the corrosion product deposition on each material.

Structure of smooth hydrocarbon CDx films with a high deuterium ratio x ~ 0.5 redeposited from T-10 tokamak D-plasma discharges (NRC Kurchatov Institute, Moscow) has been studied. For the first time, small and wide angle X-ray scattering technique using synchrotron radiation and neutron diffraction have been employed. A fractal structure of CDx films is found to consist of mass-fractals with rough border, surface fractals (with rough surface), plane scatterers and linear chains forming a branched and highly cross-linked 3D carbon network. The found fractals, including sp² clusters, are of typical size ~1-60 nm. They include a C13 fragment consisting of three interconnected aromatic rings forming a minimal fractal sp² aggregate 9 x C13. These graphene-like sp² clusters are interconnected and form a 3D lattice which can be alternatively interpreted as a highly defective graphene layer with a large concentration of vacancies. The unsaturated chemical bonds are filled with D, H atoms, linear sp² C=C, C=O, and sp³ structural elements like C-C, C-H(D), C-D2,3, C-O, O-H, COOH, CxD(H)y found earlier from the infrared spectra of CDx films, which are binding linear elements of a carbon network. The amorphous structure of CDx films has been confirmed by the results of earlier fractal structure modeling, as well as by researches with X-ray photoelectron spectroscopy which allow finding a definite similarity with the electron structure of their model analogues -- polymeric a-C:H and a-C:D films with a disordered carbon network consisting of atoms in sp³ + sp² states. [ABSTRACT FROM AUTHOR]

Promoting oxygen reduction and evolution reactions using effective catalysts hold broad significance for clean energy utilization. In this work, hollow N-doped carbon networks (N-CNs) were fabricated via interfacial dehalogenation of polyvinyl dichloride (PVDC) on 2D CoAl-layered double hydroxide (LDH) with the presence of N source and used as efficient bifunctional catalysts. BET results revealed that as-made N-CNs had very large specific surface area (SSA, 550.4 m 2 g −1 for 900 °C-annealed N-CN (N-CN9)) and abundant pore hierarchy. Additionally, interconnected graphitic carbon walls, forming separated cells, can ensure high electrical conductivity, which were formed after acid-leaching of metallic components. Remarkably, N-CN9 showed excellent bifunctional activities towards oxygen reduction and evolution reactions. Moreover, N-CN9 assembled Zn-air battery (ZAB) exhibited an operating voltage of 1.35 V under applied current density of 1.0 mA cm −2 , which is highly comparable to that of PtRu/C catalyst. Moreover, due to the pore hierarchy and large SSA, N-CN9-ZAB possessed much better rate capability and cycling stability than that of PtRu/C-ZAB. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) carbon-network-supported Si/silicide nanocomposite anodes with controllable voids are prepared using ferrosilicon, NaCl, and polyfurfuryl alcohol (PFA) resin as the starting materials. Analysis of the microstructures and the phase compositions confirms the complete removal of NaCl and the consequent formation of voids supported by a glassy carbon network, residing in between the nanostructured Si/silicide composite particles. Coin-half cell tests demonstrate the significantly improved cycling performance of the Si/silicide/carbon nanocomposites compared with that of the alloy powder without controllable voids. The electrode prepared from the coated alloy with voids maintains approximately 66% of its initial capacity after 100 cycles and its Coulombic efficiency rapidly increases to 99% after several cycles. [ABSTRACT FROM AUTHOR]

Despite the intensive studies of combining silicon (Si) and reduced graphene oxide (rGO), the architecture of Si–rGO composites still needs to be improved to maintain better electrode structure integrity and stable solid electrolyte interphase (SEI) upon extensive cycling. Herein, a conductive and protective network with rGO and CVD-implemented carbon is constructed with silicon nanoparticles (Si NPs) embedded inside for the first time. Compared with the regular Si–rGO composite with only Si NPs wrapped by rGO, Si–rGO–C composite successfully improves the electrical conductivity and structure stability. In addition to the wrapping of rGO on Si NPs, the additional carbon layer on the partially exposed Si NPs provides extra protection from fracture during volume change and helps form a stable SEI layer. Carbon rods between rGO flakes function as conductive bridges, creating an effective conductive network on a macroscopic scale. The initial capacity of Si–rGO–C composite reaches 1139 mAh g −1 and 894 mAh g −1 at 0.1 A g −1 and 1C respectively, and retains 94% of its initial capacity after 300 cycles at 1C. The electrode is stabilized at 770 mAh g −1 at 2C during rate performance testing. [ABSTRACT FROM AUTHOR]

Abstract: The commercialized LIBs employing graphite as anodes currently suffer a series of problems from the safety, theoretical capacity (372 mAh g−1) and rate capability. Herein, self-assembly mesoporous Zn ferrite (ZnFe2O4) microsphere embedded into carbon network has been synthesized by a facile method in the presence of citric acid. The Zn ferrites as an anode material with novel structure demonstrate superior electrochemical performance, with enhanced specific reversible capacity (∼1100 mAh g−1 at the specific current of 0.05 A g−1 after 100 cycles), excellent rate capability (more than 500 mAh g−1 even at the specific current of 1.1 A g−1) and good cycleability with little fading (∼97.6% after 100 cycles). The excellent cycling performance is associated with the loose Zn ferrite microsphere with numerous mesopores embedded into the carbon network, which can accommodate the severe mechanism strains and provides good electrical contact and conductivity. The superior electrochemical performance may facilitate ZnFe2O4 to be a promising alternative anode in lithium ion battery. [Copyright &y& Elsevier]

Abstract: Uniform nanospherical Li2MnSiO4/C/graphene composites have been obtained by polyethylene glycol-600 (PEG-600) assisted solid-state reaction using spherical SiO2 as precursor, and heat treatment with the mixed carbon sources (glucose, cellulose acetate and graphene oxide). The transmission electron microscope (TEM) images show that Li2MnSiO4 nanospheres with size of 50 nm are embedded in the three-dimensional (3D) nest-like carbon network. Electrochemical measurements reveal that the composites exhibit first discharge capacity of 215.3 mAh g−1 under 0.05 C, together with a stable discharge capacity of 175 mAh g−1 after 40 cycles. The 3D carbon network and the carbon layer (amorphous carbon and graphene) are favorable for improving the electrochemical performance. [Copyright &y& Elsevier]

Abstract: A polymer carbonization route was designed to synthesis carbon network-supported Fe3O4@C composites. The Fe3O4 nanoparticles with an average of ∼200nm were uniformly wrapped up in this novel carbon network. As an anode material for rechargeable lithium-ion batteries, the Fe3O4@C composites present attractive properties with a high specific capacity of 730mAhg−1 at 2C after 300 cycles. The novel carbon network plays a key role in enhancing the electrochemical performance of the composites. [Copyright &y& Elsevier]

Abstract: Percolating carbon conduction network is not only a long-time pursued scientific topic but also becomes more and more technologically important. Yet no established diagnostic tool is available. A simple two-wire transmission line (TL) model with symmetric boundary condition is suggested as working equivalent circuit model for the percolating carbon network in the insulating matrix such as polymer materials. Spatially distributed shunt capacitors of TL network are determined by the spacing between percolating backbone pathways of resistors. Deviation from the ideal RC TL behavior of the real network due to the non-uniform geometry, dangling network, random distribution of carbon fillers between the backbone pathways, etc. can be represented by modified yet parametric TL models featured by the generalization of the shunt capacitors to constant phase elements. [Copyright &y& Elsevier]

• MoSe 2 nanoflowers grown on 3D carbon network (MoSe2@rGO&CNT) were synthesized by an effective method. • The MoSe 2 nanoflowers were uniformly embedded in the 3D carbon network. • The as-prepared material exhibited a high reversible discharge capacity with good retention. 2D layered transition metal dichalcogenides deliver much higher specific capacity than the commercial graphite. However, they suffer from severe problems in practical applications such as low conductivity and poor cycling stability. Herein, we report a nanoflower-like MoSe 2 grown on a 3D carbon network synthesized by efficient hydrothermal method. It shows a high specific capacity of 717.9 mAh/g in the initial cycle, with no capacity loss from the second to the fiftieth cycle. With the help of the 3D carbon network, MoSe 2 nanoflowers present a stable structure with less agglomeration and then provide more active sites for the lithium storage, leading to better electrochemical performance. The present work suggests fabricating 3D hierarchical architectures applying simple synthetic methods could be an efficient strategy for designing advanced anode materials. [ABSTRACT FROM AUTHOR]