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Over the past 20 years, a revolution has been seen in battery research culminating with a much‐awaited Nobel Prize in Chemistry in 2019 for the development of Li‐ion batteries. New Li‐ion battery materials have been developed recently with improvements in performance. New Li battery chemistries have also emerged, exhibiting high energy density such as Li‐S, Li‐O2, Li‐metal with solid state electrolytes as well as zero‐excess Li anode metal batteries. This is tremendous progress and batteries are becoming more efficient and cheaper each year. Yet, most research in batteries is entirely focused on performance while the sustainability of all battery components making up the cell, as well as the battery chemistry itself are much overlooked. In this essay some perspectives are discussed and opinion is provided on the advancement of sustainability in battery research. [ABSTRACT FROM AUTHOR]

The aqueous oxygen reduction reaction (ORR) has recently received increased attention due to its critical role in clean and sustainable energy‐generation technologies, such as proton exchange membranes (PEM) fuel cells, alkaline fuel cells and Zn–air batteries. The sluggish kinetics associated with ORR result from multistep electron‐transfer process. The slow kinetics are partially related to the O2 adsorption process onto the catalyst, which happens at the triple‐phase boundary (TPB) of the electrocatalyst–electrolyte–oxygen interface. Hence, tremendous efforts have been devoted to improving the intrinsic properties of electrocatalysts such as active sites, electrical conductivity and porosity. Engineering the electrocatalyst's interfacial properties is another critical issue in ORR, however less described in the literature. The surface of the catalyst provides the microenvironment for the triple boundary interface reaction, which directly influences its electrocatalytic activity and the kinetics. This Minireview is a summary of the existing literature on manipulating the interfacial surface of non‐precious metal catalysts at the triple point between the solid catalyst, the aqueous electrolyte and the O2 gas with the aim of improving the ORR efficiency. Various approaches towards improving the wettability and nanostructuring the catalyst surface to boost the activity of the surface‐active sites and provide improved stability are discussed. Promoting adsorption: The sluggish kinetics resulting from multistep electron transfer processes is the main concern in ORR. Promoting O2 adsorption, which happens on the triple‐phase boundary (TPB) of electrocatalyst–electrolyte–oxygen interface can overcome the slow kinetics. In this paper we review some of the existing surface engineering strategies in the literature aiming to manipulate the triple point boundary (TPB) to promote the aqueous ORR. [ABSTRACT FROM AUTHOR]

Atomically dispersed iron–nitrogen–carbon catalysts are promised, low‐cost, and high‐performance electrocatalysts for the Oxygen Reduction Reaction (ORR) in fuel cells. However, most Fe–N–C materials are produced via pyrolysis at a high temperature and it is difficult to characterise the precise Fe–N configurations. This can lead to confusion surrounding the best chemical and coordination environment for Fe and understanding the subsequent ORR mechanisms. In this work, Fe porphyrin is used to produce a specific Fe–N environment, therefore allowing the role and activity of this environment to be studied. Carbon nanotubes (CNTs) are covalently functionalized with iron 5,10,15,20‐triphenylporphyrin (FeTPP) motifs via aryl diazonium methodology, enabling the exact role of only the Fe‐Pyrrolic N4 configuration of FeTPP in ORR to be studied and better understood. Upon covalent functionalization, a high electrochemical active site density of 1.12 × 1015 sites cm−2, approximately six‐fold more than that of noncovalently functionalized samples with 12.7% electrochemical active site. The heightened active site density and superior electrochemical active site utilization (12.7%) lead to the more favorable 4‐electron pathway for the ORR. Furthermore, a preliminary discussion regarding the selectivity of the ORR pathway is initiated. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 reduction reaction (CO2RR) to value‐added chemicals with renewable electricity is a promising method to decarbonize parts of the chemical industry. Recently, single metal atoms in nitrogen‐doped carbon (MNC) have emerged as potential electrocatalysts for CO2RR to CO with high activity and faradaic efficiency, although the reaction limitation for CO2RR to CO is unclear. To understand the comparison of intrinsic activity of different MNCs, two catalysts are synthesized through a decoupled two‐step synthesis approach of high temperature pyrolysis and low temperature metalation (Fe or Ni). The highly meso‐porous structure results in the highest reported electrochemical active site utilization based on in situ nitrite stripping; up to 59±6% for NiNC. Ex situ X‐ray absorption spectroscopy (XAS) confirms the penta‐coordinated nature of the active sites. The catalysts are amongst the most active in the literature for CO2 reduction to CO. The density functional theory calculations (DFT) show that their binding to the reaction intermediates approximates to that of Au surfaces. However, it is found that the turnover frequencies (TOFs) of the most active catalysts for CO evolution converge, suggesting a fundamental ceiling to the catalytic rates. [ABSTRACT FROM AUTHOR]

Review: 199 refs. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have attracted more and more attention for scalable electrical energy storage due to the abundance and wide distribution of Na resources. However, the anode still remains a great challenge for the application of SIBs. Here the production of uniform hard carbon microtubes (HCTs) made from natural cotton through one simple carbonization process and their application as an anode are reported. The study shows that the electrochemical performance of the HCTs is seriously affected by the carbonization temperature due to the difference in their microstructure and heteroatomic content. The HCTs carbonized at 1300 °C deliver the highest reversible capacity of 315 mAh g−1 and good rate capability due to their unique tubular structure. This contribution not only provides a new approach for the preparation of hard carbon materials with unique tubular microstructure using natural inspiration, but it also deepens the fundamental understanding of the sodium storage mechanism. [ABSTRACT FROM AUTHOR]

Materials that combine the functionalities of both of proteins and graphene are of great interest for the engineering of biosensing, drug delivery, and regenerative devices. Graphene oxide (GO) offers an opportunity to design GO‐protein interactions but the need for harsh reduction processes to enable GO photoexcitation remains a limitation. A disinfector‐assisted low temperature method to reduce GO‐protein materials and fabricate surgical dressings with tuneable photothermal efficiency and bioactive properties for the postoperative treatment of melanoma is reported. The approach harnesses the capacity of 70% ethanol to penetrate the protein shell of microorganisms to infiltrate GO‐protein complexes and reduce GO at low temperature (85 °C) while maintaining the material structure and bioactivity. Both experiments and coarse‐grained simulations are used to describe the reduction process and assess the material properties. In vitro and in vivo validation revealed the capacity of the dressings to prevent tumor recurrence and promote healing after tumor resection. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries as a prospective alternative to lithium‐ion batteries are facing the challenge of developing high‐performance, low‐cost and sustainable anode materials. Hard carbons are appropriate to store sodium ions, but major energy and environmental concerns during their fabrication process (i.e., high‐temperature carbonization) have not been properly assessed. Furthermore, the rational design of high‐performing hard carbon anodes is usually limited by the conventional direct carbonization of organic precursors. Here, the hydrothermal carbonization process is employed as a versatile pre‐treatment method of renewable precursors, followed by high‐temperature carbonization, for producing advanced hard carbon anodes. The critical role of hydrothermal pre‐treatment in regulating the structure for an optimized performance of hard carbon anodes is elucidated, while revealing the sodium‐ion storage mechanism using electrochemical kinetic calculations, advanced characterization and multi‐scale modeling. Furthermore, the environmental impacts of hydrothermal pre‐treatment and subsequent carbonization are evaluated using life cycle assessment compared to direct carbonization. By comparing hard carbon anodes with and without the hydrothermal pre‐treatment, it is verified that the additional hydrothermal process is responsible for enhanced electrochemical performance, increased carbon yields and reduced carbon emissions. The work provides a systematic understanding of functions and energy consumptions of hydrothermal systems to achieve next‐generation sustainable sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs) are prospective candidates for large‐scale energy storage systems cause of their abundant resources. However, unsatisfactory rate and cycling performance of carbon‐based anodes present a bottleneck for the applications of SIBs/PIBs due to the large sizes of sodium/potassium ions. Herein, oxygen‐doped vertically aligned carbon aerogels (VCAs) with hierarchically tailored channels are synthesized as anodes in SIBs/PIBs via a controllable unidirectional ice‐templating technique. VCA‐3 (cooling rate of 3 K min−1) delivers the highest reversible capacity of ≈298 mAh g−1 at 0.1 C with an excellent cycling performance over 2000 cycles at 0.5 C for SIBs, while VCA‐5 manifests a superior capacity of ≈258 mAh g−1 at 0.1 C with an 82.7% retention over 1000 cycles at 0.5 C for PIBs. Moreover, their full cells demonstrate the promising potential of VCAs in applications. This novel controllable ice‐templating strategy opens unique avenues to tune the construction of hollow aligned channels for shortening ion‐transport pathways and ensuring structural integrity. New insights into structure‐performance correlations regulated by the cooling rates of an ice‐templating strategy and design guidelines for electrodes applicable in multiple energy storage technologies are reported. [ABSTRACT FROM AUTHOR]

Heteroatom doping has been proved to effectively enhance the sloping capacity, nevertheless, the high sloping capacity almost encounters a conflict with the disappointing initial Coulombic efficiency (ICE). Herein, we propose a heteroatom configuration screening strategy by introducing a secondary carbonization process for the phosphate‐treated carbons to remove the irreversible heteroatom configurations but with the reversible ones and free radicals remaining, achieving a simultaneity between the high sloping capacity and ICE (≈250 mAh g−1 and 80 %). The Na storage mechanism was also studied based on this "slope‐dominated" carbon to reveal the reason for the absence of the plateau. This work could inspire to distinguish and filter the irreversible heteroatom configurations and facilitate the future design of practical "slope‐dominated" carbon anodes towards high‐power Na‐ion batteries. [ABSTRACT FROM AUTHOR]

Heteroatom doping has been proved to effectively enhance the sloping capacity, nevertheless, the high sloping capacity almost encounters a conflict with the disappointing initial Coulombic efficiency (ICE). Herein, we propose a heteroatom configuration screening strategy by introducing a secondary carbonization process for the phosphate‐treated carbons to remove the irreversible heteroatom configurations but with the reversible ones and free radicals remaining, achieving a simultaneity between the high sloping capacity and ICE (≈250 mAh g−1 and 80 %). The Na storage mechanism was also studied based on this "slope‐dominated" carbon to reveal the reason for the absence of the plateau. This work could inspire to distinguish and filter the irreversible heteroatom configurations and facilitate the future design of practical "slope‐dominated" carbon anodes towards high‐power Na‐ion batteries. [ABSTRACT FROM AUTHOR]

Electrochemical clean energy conversion and the production of sustainable chemicals are critical in the journey to realizing a truly sustainable society. To progress electrochemical storage and conversion devices to commercialization, improving the electrocatalyst performance and cost are of utmost importance. Research into dual‐metal atom catalysts (DACs) is rising in prominence due to the advantages of these sites over single‐metal atom catalysts (SACs), such as breaking scaling relationships for the adsorption energy of reaction intermediates and synergistic effects. This review provides an examination of the fundamental theoretical principles and experimental electrochemical performance of DACs in idealized half cells, as well as fuel cells, before proceeding to analyze the methods used for producing and identifying DACs. Current challenges and potential future research directions of DACs are also discussed. [ABSTRACT FROM AUTHOR]

Biomass is recognized as an ideal CO2 neutral, abundant, and renewable resource substitute to fossil fuels. The rich proton content in most biomass derived materials, such as ethanol, 5‐hydroxymethylfurfural (HMF) and glycerol allows it to be an effective hydrogen carrier. The oxidation derivatives, such as 2,5‐difurandicarboxylic acid from HMF, glyceric acid from glycerol are valuable products to be used in biodegradable polymers and pharmaceuticals. Therefore, combining biomass‐derived compound oxidation at the anode and hydrogen evolution reaction at the cathode in a biomass electrolysis or photo‐reforming reactor would present a promising strategy for coproducing high value chemicals and hydrogen with low energy consumption and CO2 emissions. This review aims to combine fundamental knowledge on photo and electro‐assisted catalysis to provide a comprehensive understanding of the general reaction mechanisms of different biomass‐derived molecule oxidation. At the same time, catalyst requirements and recent advances for various feedstock compounds are also reviewed in detail. Technoeconomic assessment and life cycle analysis are performed on various feedstocks to assess the relative benefits of various processes, and finally critical prospects are given on the challenges and opportunities for technology development to meet the sustainability requirement of the future global energy economy. [ABSTRACT FROM AUTHOR]

Atomically dispersed transition metal‐nitrogen‐carbon catalysts are emerging as low‐cost electrocatalysts for the oxygen reduction reaction in fuel cells. However, a cost‐effective and scalable synthesis strategy for these catalysts is still required, as well as a greater understanding of their mechanisms. Herein, iron, nitrogen co‐doped carbon spheres (Fe@NCS) have been prepared via hydrothermal carbonization and high‐temperature post carbonization. It is determined that FeN4 is the main form of iron existing in the obtained Fe@NCS. Two different precursors containing Fe2+ and Fe3+ are compared. Both chemical and structural differences have been observed in catalysts starting from Fe2+ and Fe3+ precursors. Fe2+@NCS‐A (starting with Fe2+ precursor) shows better catalytic activity for the oxygen reduction reaction. This catalyst is studied in an anion exchange membrane fuel cell. The high open‐circuit voltage demonstrates the potential approach for developing high‐performance, low‐cost fuel cell catalysts. [ABSTRACT FROM AUTHOR]

Insufficient light absorption and low carrier separation/transfer efficiency constitute two key issues that hinder the development of efficient photocatalytic hydrogen production. Here, multishell ZnS/CoS2 bisulfide microspheres with gradient distribution of Zn based on the heat diffusion theory are designed. The Zn distribution can be adjusted by regulating the heating rate and manipulating the diffusion coefficients of the different elements conforming the multishell photocatalyst. Because of the unique structure, a gradient energy level is created from the core to the exterior of the multishell microspheres, which effectively facilitates the exciton separation and electron transfer. In addition, stronger light absorption and larger specific surface area have been achieved in the multishell ZnS/CoS2 photocatalysts. As a result, the multishell ZnS/CoS2 microspheres with gradient distribution of Zn exhibit a remarkable hydrogen production rate of 8001 µmol g−1 h−1, which is 3.5 times higher than that of the normal multishell ZnS/CoS2 particles with well‐distributed Zn and 11.3 times higher than that of the mixed nonshell ZnS and CoS2 particles. This work demonstrates for the first time that controlling the diffusion rate of the different elements in the semiconductor is an effective route to simultaneously regulate morphology and structure to design highly efficient photocatalysts. [ABSTRACT FROM AUTHOR]

A deeper understanding of the water‐splitting hydrogen evolution reaction (HER) mechanism during photocatalytic processes is crucial for the rational design of efficient photocatalysts. In particular, the HER mechanism promoted by multielement hybrid structures remains extremely challenging and elusive. Herein, an in situ photoelectrochemical/Raman measurement system is employed to monitor the HER mechanism of hybrid nanostructures under realistic working conditions via operando Raman spectra and linear‐sweep voltammetry curves. As a proof of concept, tunable composition transition metal dichalcogenides MoS2xSe2(1−x) nanosheets are used as a model photocatalyst to unveil the corresponding photocatalytic mechanism. The spectroscopic studies reveal that hydrogen atoms can be adsorbed to active sulfur and selenium atoms via intermediate species formed during the photocatalytic process. More importantly, the studies demonstrate that an exponential relationship exists between the number of reactive electrons and the Raman intensity of intermediate species, which can serve as a guideline to directly evaluate the HER performance in photocatalysts by comparing the Raman intensities of the intermediate species. As a simple, intuitive, and general analytical method, the designed operando Raman measurement approach provides a new tool for elucidating catalytic reaction mechanisms in a realistic and complex environment; and strategically improving H2 production performance of multielement photocatalysts. [ABSTRACT FROM AUTHOR]

Hard carbons are among the most promising materials for alkali‐ion metal anodes. These materials have a highly complex structure and understanding the metal storage and migration within these structures is of utmost importance for the development of next‐generation battery technologies. The effect of different carbon structural motifs on Li, Na, and K storage and diffusion are probed using density functional theory based on experimental characterizations of hard carbon samples. Two carbon structural models—the planar graphitic layer model and the cylindrical pore model—are constructed guided by small‐angle X‐ray scattering and transmission electron microscopy characterization. The planar graphitic layers with interlayer distance <6.5 Å are beneficial for metal storage, but do not have significant contribution to rapid metal diffusion. Fast diffusion is shown to take place in planar graphitic layers with interlayer distance >6.5 Å, when the graphitic layer separation becomes so wide that there is negligible interaction between the two graphitic layers. The cylindrical pore model, reflecting the curved morphology, does not increase metal storage, but significantly lowers the metal migration barriers. Hence, the curved carbon morphologies are shown to have great importance for battery cycling. These findings provide an atomic‐scale picture of the metal storage and diffusion in these materials. [ABSTRACT FROM AUTHOR]

Sustainable energy production at an acceptable cost is key for its widespread application. At present, noble metals and metal oxides are the most widely used for electrocatalysis, but they suffer from low selectivity, poor durability, and scarcity. Because of this, metal‐free carbons have become the subject of great interest as promising alternative electrocatalysts for energy conversion and storage devices, and remarkable progress has been accomplished in the advance of metal‐free carbons as electrocatalysts for renewable energy technologies. Particularly interesting are 3D porous carbon architectures, which exhibit outstanding features for electrocatalysis applications, including broad range of active sites, interconnected porosity, high conductivity, and mechanical stability. This review summarizes the latest advances in 3D porous carbon structures for oxygen and hydrogen electrocatalysis. The structure–performance relationship of these materials is consequently rationalized and perspectives on creating more efficient 3D carbon electrocatalysts are suggested. [ABSTRACT FROM AUTHOR]

High activity, selectivity and recyclability are crucial parameters in the design of performant catalysts. Furthermore, depletion of platinum‐group metals (PGM) drives further research towards highly available metal‐based catalysts. In this framework, iron‐based active sites supported on nitrogen‐doped carbon materials (Fe/N@C) have been explored to tackle important applications in organic chemistry, for both oxidation and reduction of C−O/C−N bonds, as well as in electrocatalysis for energy applications. This versatile reactivity makes them ideal substitutes to PGM‐based catalysts, being based on abundant elements. Despite important advances in material science and characterisation techniques allowing the analysis of heterogeneous/electro‐ catalysts at the atomic scale, the nature of the catalytically active sites in Fe/N@C remains elusive. Most recent theoretical studies point at individual FeNx single sites as the origin of the catalytic activity. Although their identification is still challenging with current technology, establishing their real nature will foster further research on these PGM‐free and redox‐polyvalent catalysts. In this review, we provide an overview of their applications in both thermal and electrochemical processes. Throughout the review, we highlight the different characterisation techniques employed to gain insight into the catalyst's active sites. [ABSTRACT FROM AUTHOR]

A hard templating method, using SBA‐15 in combination with glucose solution and different heteroatom precursors, has been employed to investigate the influence of the different heteroatom dopants nitrogen, boron, sulfur, and phosphorus on carbon electrocatalysts for the oxygen reduction reaction. Samples were synthesized under the same conditions and resulted in a similar morphology and surface areas around 1000 m2/g. Incorporating nitrogen into the carbon matrix was found to be easier than for boron or phosphorus, while sulfur doping proved problematic and only yielded 2 at% of sulfur or less. Different dopant concentrations as well as a combination of dopants suggested that nitrogen was the only heteroatom exerting an actual influence on the catalytic activity, resulting in higher electron transfer numbers. The other dopants exhibited a similar performance regardless of the dopant content, though slightly improved when compared to an undoped control sample. These findings indicate that incorporated nitrogen can act as catalytic sites, while boron, sulfur and phosphorus can enhance the catalytic activity by possibly creating defects in the carbon matrix. [ABSTRACT FROM AUTHOR]

Abstract: An effective strategy is proposed to enhance the oxygen reduction reaction (ORR) performance of multiwall carbon nanotubes (MWCNTs) in both acid and alkaline electrolytes by coating them with a layer of biomass derivative N‐doped hydrothermal carbons. The N‐doped amorphous carbon coating plays triple roles: it (i) promotes the assembly of MWCNTs into a 3D network therefore improving the mass transfer and thus increasing the catalytic activity; (ii) protects the Fe‐containing active sites, present on the surface of the MWCNTs, from H2O2 poisoning; (iii) creates nitrogenated active sites and hence further enhances ORR activity and robustness. [ABSTRACT FROM AUTHOR]

Review: [171 refs. [ABSTRACT FROM AUTHOR]

Dual‐Metal Atom Electrocatalysts In article number 2102715, Maria Magdalena Titirici, Ifan E. L. Stephens and co‐workers comprehensively review dual‐metal atom electrocatalysts, providing insight into how this class of materials could lead to a step change in catalytic performance over single‐atom and metallic electrocatalysts. They discuss key challenges and opportunities in the synthesis, characterization, and electrochemical testing of dual‐metal atom electrocatalysts. [ABSTRACT FROM AUTHOR]

Keywords: CO 2 reduction; electrocatalysts; N 2 reduction; O 2 evolution; O 2 reduction EN CO 2 reduction electrocatalysts N 2 reduction O 2 evolution O 2 reduction 1 1 1 01/25/22 20220120 NES 220120 B Dual-Metal Atom Electrocatalysts b In article number 2102715, Maria Magdalena Titirici, Ifan E. L. Stephens and co-workers comprehensively review dual-metal atom electrocatalysts, providing insight into how this class of materials could lead to a step change in catalytic performance over single-atom and metallic electrocatalysts. CO 2 reduction, electrocatalysts, N 2 reduction, O 2 evolution, O 2 reduction They discuss key challenges and opportunities in the synthesis, characterization, and electrochemical testing of dual-metal atom electrocatalysts. [Extracted from the article]

A simple and efficient polymer grafting onto hydrothermal carbonization (HTC)-derived materials is described. The method pertains to the Diels-Alder cycloaddition reaction of furan moieties present on the surface of a HTC material with the maleimide groups stemming from a maleimide protected poly(ethylene glycol) (Me-PEG-MI) by a retro Diels-Alder reaction. The precursor polymer, HTC material, and final product are characterized. Successful grafting is confirmed by elemental analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and dispersion studies. [ABSTRACT FROM AUTHOR]

Electrocatalysis: 3D Carbon Materials for Efficient Oxygen and Hydrogen Electrocatalysis (Adv. Keywords: 3D porous carbons; electrocatalysis; hydrogen evolution; oxygen evolution; oxygen reduction 3D porous carbons, electrocatalysis, hydrogen evolution, oxygen evolution, oxygen reduction. [Extracted from the article]

Porous structure design is generally considered to be a reliable strategy to boost ion transport and provide active sites for disordered carbon anodes of Na‐ion batteries (NIBs). Herein, a type of waste cork‐derived hard carbon material (CC) is reported for efficient Na storage via tuning the pore species. Benefiting from the natural holey texture of this renewable precursor, CCs deliver a novel hierarchical porous structure. The effective skeletal density test combined with small angle X‐ray scattering analysis (SAXS) is used to obtain the closed pore information. Based on a detailed correlation analysis between pore information and the electrochemical performance of CCs, improving pyrolysis temperature to reduce open pores (related to initial capacity loss) and increase closed pores (related to plateau capacity) endows an optimal CC with a high specific capacity of ≈360 mAh g−1 in half‐cells and a high energy density of 230 Wh kg−1 in full‐cells with a capacity retention of 71% after 2000 cycles at 2C rate. The bioinspired high temperature pore‐closing strategy and the new insights about the pore structure–performance relationship provide a rational guide for designing porous carbon anode of NIBs with tailored pore species and high Na storage capacity. [ABSTRACT FROM AUTHOR]

Na‐ion hybrid capacitors consisting of battery‐type anodes and capacitor‐style cathodes are attracting increasing attention on account of the abundance of sodium‐based resources as well as the potential to bridge the gap between batteries (high energy) and supercapacitors (high power). Herein, hierarchically structured carbon materials inspired by multiscale building units of cellulose from nature are assembled with cellulose‐based gel electrolytes into Na‐ion capacitors. Nonporous hard carbon anodes are obtained through the direct thermal pyrolysis of cellulose nanocrystals. Nitrogen‐doped carbon cathodes with a coral‐like hierarchically porous architecture are prepared via hydrothermal carbonization and activation of cellulose microfibrils. The reversible charge capacity of the anode is 256.9 mAh g−1 when operating at 0.1 A g−1 from 0 to 1.5 V versus Na+/Na, and the discharge capacitance of cathodes tested within 1.5 to 4.2 V versus Na+/Na is 212.4 F g−1 at 0.1 A g−1. Utilizing Na+ and ClO4− as charge carriers, the energy density of the full Na‐ion capacitor with two asymmetric carbon electrodes can reach 181 Wh kg−1 at 250 W kg−1, which is one of the highest energy devices reported until now. Combined with macrocellulose‐based gel electrolytes, all‐cellulose‐based quasi‐solid‐state devices are demonstrated possessing additional advantages in terms of overall sustainability. [ABSTRACT FROM AUTHOR]

Highlights from the article: Sodium-Ion Batteries: Hard-Soft Carbon Composite Anodes with Synergistic Sodium Storage Performance (Adv. Funct. Keywords: closed pores; hard carbon; sodium-ion batteries; soft carbon; synergistic effect Closed pores, hard carbon, sodium-ion batteries, soft carbon, synergistic effect.

A series of hard–soft carbon composite materials is produced from biomass and oil waste and applied as low‐cost anodes for sodium‐ion batteries to study the fundamentals behind the dependence of Na storage on their structural features. A good reversible capacity of 282 mAh g−1 is obtained at a current density of 30 mA g−1 with a high initial Coulombic efficiency of 80% at a carbonization temperature of only 1000 °C by adjusting the ratio of hard to soft carbon. The performance is superior to the pure hard or soft carbon anodes produced at the same temperatures. This synergy between hard and soft carbon resulting in an excellent performance is due to the blockage of some open pores in hard carbon by the soft carbon, which suppresses the solid electrolyte interface formation and increases the reversible sodium storage capacity. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries have received tremendous attention due to their superior theoretical energy density of 2600 Wh kg−1, as well as the abundance of sulfur resources and its environmental friendliness. Polymer binders as an indispensable component in cathodes play a critical role in maintaining the structural integrity and stability of electrodes. Additionally, multifunctional polymer binders have been involved in Li–S batteries to benefit electrochemical performance by mitigating the shuttle effect, facilitating the electron/ion transportation, and propelling the redox kinetics. In the context of the significant impact of binders on the performance of Li–S batteries, recent progress in research on polymer binders in sulfur cathodes is herein summarized. Focusing on the functions and effects of the polymer binders, the authors hope to shed light on the rational construction of robust and stable sulfur cathode for high‐energy‐density Li–S batteries. Perspectives regarding the future research opportunities in Li–S batteries are also discussed. Polymer binders in lithium–sulfur batteries play a critical role in maintaining the structural integrity and stability of the electrode as an indispensable component. In this review, recent progress in research on polymer binders in sulfur cathodes is summarized, focusing on the rational design strategies of multifunctional polymer binders toward better lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]