Hard carbons have shown considerable promise as anodes for emerging sodium-ion battery technologies. Current understanding of sodium-storage behaviour in hard carbons attributes capacity to filling of graphitic interlayers and pores,...

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.

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.

Hydrogen peroxide is a widely used and important chemical in industry. A two-electron electrochemical oxygen reduction reaction (2e– ORR) is a clean and on-site method for H2O2 production. Here, we report metal-free catalysts (mesoporous carbon hollow spheres, MCHS) for high-efficiency H2O2 production in neutral electrolytes (0.1 M PBS). The selectivity of H2O2 on MCHS catalysts is higher than 90% at a wide range of potentials (0.35–0.62 V), and it can reach 99.9% at a potential of 0.57 V. These catalysts show some of the best performances for H2O2 production in neutral electrolytes. It is preferable to develop H2O2 catalysts in a neutral environment, as the pH of the stabilizers used for H2O2 is also close to neutral. The outstanding activity of our catalyst comes from a combination of factors such as suitable porosity, the content of oxygen functional groups, and the types of different species of oxygen functional groups. First-principles simulations show that a catalyst with suitable mixed oxygen and COOH functional groups plays an important role in the catalytic formation of H2O2. The reported metal-free catalysts are promising catalysts for high-efficiency production of H2O2 in the future.

Magnesium–sulfur batteries promise high volumetric energy density, enhanced safety, and low cost for electrochemical energy storage. The current obstacles to practical applications of reliable magnesium–sulfur batteries are finding electrolytes that can meet a multitude of rigorous requirements along with efficient sulfur cathodes and magnesium anodes. This review highlights recent advances in designing better electrolytes, cathodes, and anodes. A suitable electrolyte for magnesium–sulfur batteries should allow to reversibly electroplate/strip divalent magnesium ions and should be compatible with the sulfur cathode and the other cell's components. Another challenge to be addressed is the careful engineering of the interface and microstructure in the sulfur scaffold to effectively mitigate the soluble magnesium polysulfide shuttle and to enhance the reaction kinetics. We highlight that the ongoing research in this field encourages the fundamental understanding of the reaction mechanisms and the interplay among the different components by diverse characterization techniques.