Exploitation of the efficient and cost-effective electrode materials is urgently desirable for the development of advanced energy devices. With the unique features of good electronic conductivity, structure flexibility, and desirable physicochemical property, carbon-based nanomaterials have attracted enormous research attention as efficient electrode materials. Electronic and microstructure engineering of carbon-based nanomaterials are the keys to regulate the electrocatalytic properties for the specific redox reactions of advanced metal-based batteries. However, the critical roles of carbon-based electrocatalysts for rechargeable metal batteries have not been comprehensively discussed. With the basic introduction on the electronic and microstructure engineering strategies, we summarize the recent advances on the rational design of carbon-based electrocatalysts for the important redox reactions in various metal-air batteries and metal-halogen batteries. The relationships between the composition, structure, and the electrocatalytic properties of carbon-based materials were well-addressed to enhance the battery performance. The overview of present challenges and opportunities of the carbon-based active materials for future energy-related applications was also discussed.

Rechargeable aqueous zinc-iodine batteries have received extensive attention due to their inherent advantages such as low cost, flame retardancy and safety. To address the safety concern associated with Zn dendrites, tin functional layer is introduced to the Zn surface via a spontaneous galvanic replacement reaction. This provides rapid deposition kinetics, thereby achieving the uniform Zn plating/stripping with a low overpotential (13.9 mV) and good stability for over 900 h. Importantly, the coupling of the advanced Zn anode with iodine in Zn-I₂ battery exhibits a high specific capacity of 196.4 mAh·g⁻¹ with high capacity retention (90.7%). This work provides a reliable strategy to regulate the reversible redox of zinc for advanced rechargeable batteries.

Water electrolysis is an available way to obtain green hydrogen. The development of highly efficient electrocatalysts is a current research hotspot for water splitting, but it remains challenging. Herein, we demonstrate the synthesis of a robust bifunctional multi-metal electrocatalysts toward water splitting via the rapid Joule-heating conversion of metal precursors. The composition and morphology were well regulated via altering the ratio of metal precursors. In particular, the trimetal MoC/FeO/CoO/carbon cloth (CC) electrode revealed the outstanding bifunctional electrocatalytic performance due to the unique composition and large electrochemical active surface area. Typically, the MoC/FeO/CoO/CC catalyst needed low overpotentials of 121 and 268 mV to reach 10 mA·cm^-2 toward HER and OER in 1 mol·L^-1 KOH solution, respectively. When used as both cathode and anode, a small potential of 1.69 V was required to achieve 10 mA·cm^-2 for overall water splitting and an impressive stability for 25 h was observed. This facile and rapid Joule heating strategy offers guideline for rational manufacture of bimetal or multi-metal electrocatalysts toward diverse application.

Rechargeable lithium-iodine (Li-I₂) battery is a promising energy storage system because of the high energy and power density. However, the shuttle effects of iodine species and the unstable features of I₂ block the practical applications of Li-I₂ batteries. Herein, a dual heteroatom doped porous carbon cloth is fabricated as the host material for lithium iodide (LiI). Specifically, the self-standing nitrogen, phosphorus co-doped carbon cloth with high LiI loading exhibits a large specific capacity (221 mAhdg^-1 at 1 C), excellent rate capability (95.8% capacity retention at 5 C) and superior long cycling stability (2, 000 cycles with a capacity retention of 96%). Electrochemical kinetic analysis confirms the dominant contribution of capacitive effects at high scan rates, which is responsible for the good high-rate performance. The improved electrochemical performance mainly stems from two unique features of nitrogen, phosphorus co-doped porous carbon cloth. Heteroatom doping provides extra active sites for strong adsorption of iodine species while the highly porous structure with large surface area favors the capacitive effects at high rates. This work provides a facile yet efficient approach to regulating both redox reaction and capacitive effects via adjusting surface composition and pore structure of carbon materials for enhanced battery performance.