Promoting oxygen reduction reaction kinetics through manipulating electron redistribution in CoP/Cu3P@NC for aqueous/flexible Zn–air batteries†

Abstract

Zinc–air batteries (ZABs) are considered a promising energy storage technology due to their high energy density and environmental friendliness. However, the development of efficient and durable oxygen reduction reaction (ORR) catalysts remains a challenge. Herein, we report the synthesis of a highly efficient CoP/Cu₃P@NC catalyst using a Zn-MOF template, which was transformed into N- and C-doped bimetallic phosphides via high-temperature phosphating. The CoP/Cu₃P@NC-based ZAB exhibits remarkable performance with an open-circuit voltage of 1.50 V, a peak power density of 215 mW cm⁻², and a specific capacity of 691 mA h g_zn⁻¹, outperforming conventional Pt/C-based ZABs. The catalyst maintained 93.5% of its initial activity after 300 h of cycling, demonstrating its excellent long-term stability. Furthermore, CoP/Cu₃P@NC was applied in flexible ZABs, achieving a power density of 74 mW cm⁻² and showing stable performance under various bending conditions. The superior performance is attributed to the synergistic effects of Co and Cu, optimized structural properties, and high porosity, enhancing mass transfer and oxygen activation. These results suggest that CoP/Cu₃P@NC is a highly promising ORR catalyst for next-generation ZABs, offering both high efficiency and durability in flexible and conventional energy storage applications.