Atomic-level coupled spinel@perovskite dual-phase oxides toward enhanced performance in Zn–air batteries

Abstract

Interface engineering has been proved to be an efficient strategy for boosting electrocatalytic performance and has attracted increasing interest in past few decades. Herein, Co₃O₄@LaCoO₃ heterojunctions with abundant oxygen vacancies, subtle lattice distortion, and atomic-level coupled interfaces were synthesized in a nonequilibrium stoichiometric ratio. The synthesized product shows exceptional bifunctional catalytic activity and robust stability in the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). As demonstrated by high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and extended X-ray absorption fine structure spectroscopy (XAFS), the heterojunction structure between Co₃O₄ and LaCoO₃ was formed, which is beneficial for its electrocatalytic properties. The enhanced catalytic capacity is also evidenced by the results of experimental measurements and first-principles calculations. Furthermore, the Co₃O₄@LaCoO₃ assembled Zn–air batteries (including routine liquid batteries and flexible solid-type batteries) exhibit a large peak power density, high open-circuit potential, and a long-term cycle life. This work affords rational design strategies of spinel@perovskite dual-phase oxides and provides potential applications in wearable electronic devices.