Integrating High-Entropy Alloy Nanocatalysts with Aligned Porous Air Electrode for High-Power Zinc-Air Battery

Zinc-air batteries (ZABs) hold great promise as next-generation energy storage technologies thanks to their high energy density, low cost, and good safety. However, developing air electrodes that can achieve high power density in ZABs remains a grand challenge. Herein, an integrated air electrode comprising an aligned porous carbon film uniformly and densely decorated with ultrasmall high-entropy alloy nanoparticles (HEA-NPs) is presented. This design simultaneously meets the stringent requirements for fast reaction kinetics and efficient mass/electron transport imposed by high-rate operation. Comprehensive structural and electrochemical analyses reveal that the air electrode's tailored pore size distribution and vertically aligned channels furnish unimpeded pathways for the transport of ions, gases, and electrons. Meanwhile, the HEA-NPs, with high bifunctional catalytic activity and an enriched number of active sites, dramatically accelerate the oxygen reduction and evolution reactions. Consequently, a quasi-solid-state ZAB employing this air electrode achieves an outstanding power density of 545 mW cm^-2 and stable operation for over 165 h at a high current density of 50 mA cm^-2. By elucidating a clear structure-performance relationship, this study offers a valuable guideline for the rational design of porous electrodes for high-power-density ZABs and beyond.