Realization of Efficient 4e − Oxygen Reduction via Heterojunction‐Phosphorus Vacancy Synergy for High‐Performance Zinc–Air Batteries

Abstract The development of efficient four‐electron (4e − ) oxygen reduction reaction (ORR) catalysts is pivotal for advancing sustainable energy conversion. Herein, a nitrogen–carbon encapsulated Cu 3 P/CePO 4 heterojunction with phosphorus vacancies (Cu 3 P/CePO 4 @NC) is constructed, achieving exceptional ORR activity via dual electronic and structural modulation. In situ infrared spectroscopy confirms the absence of H 2 O 2 intermediates and accelerated O─O bond dissociation, strongly supporting a dominant 4e − reduction pathway. Density functional theory (DFT) calculations reveal that the synergistic effect of the heterojunction‐phosphorus vacancy facilitates interfacial charge‐transfer, optimizes the adsorption energies of reaction intermediates, and significantly reduces the energy barrier of the rate‐determining step. Besides, the strong hydrophilicity and enlarged electrochemically active surface area (ECSA) facilitate thorough electrolyte infiltration and sufficient exposure of active sites, collectively accelerating ORR kinetics. Zinc‐air batteries (ZABs) utilizing the Cu 3 P/CePO 4 @NC catalyst deliver an outstanding peak power density of 209.35 mW cm −2 and maintain stable discharge operation over 1000 h, demonstrating superior long‐term durability. Furthermore, flexible ZABs, incorporating Cu 3 P/CePO 4 @NC achieve a power density of 91.29 mW cm −2 , maintaining stable performance under various bending angles, thereby highlighting its potential for flexible energy storage applications.