Alloying Confined Regulation of Nanoparticles in a Hierarchically Directed Porous Carbon for Zinc-Air Batteries

The rational design of non-noble metal-based electrocatalysts with efficient bifunctional catalytic activity is critical for the widespread application of zinc-air batteries (ZABs). In this study, an FeNi alloy encapsulated three-dimensional honeycomb-like network structure of carbon aerogels (FeNi/CAs) electrocatalyst was constructed using directional freeze-drying technology. The innovative architecture, combined with the synergistic effect between Fe and Ni, endows the FeNi/CAs catalyst with outstanding bifunctional catalytic activity compared with the introduction of a single metal in carbon aerogels. Specifically, the catalyst achieves a high half-wave potential (E_1/2) of 0.90 V for the oxygen reduction reaction (ORR) and excellent stability with a negligible shift of E_1/2 (9 mV) after 2000 cycles. Moreover, the FeNi/CAs catalyst exhibits a smaller potential difference (ΔE = 0.68 V) between the ORR and oxygen evolution reaction (OER), highlighting its superior bifunctional activity. Furthermore, the rechargeable ZABs with FeNi/CAs catalysts show remarkable power density (226 mW cm^-2) and energy density (985 mWh kg^-1), as well as over 1200 h of cycling stability. Additionally, the discharge rate performance of the assembled flexible all-solid-state battery based on this catalyst remains stable under different bending angles, suggesting its robustness and potential for use in wearable electronic devices. This work provides a compelling strategy for the construction of advanced electrocatalysts by leveraging hierarchical structural features and metal synergy, paving the way for high-performance and durable ZABs in next-generation energy storage applications.