Novel medium entropy perovskite oxide Sr(FeCoNiMo)1/4O3− for zinc-air battery cathode

It is widely recognized that the development of ZABs is impeded by the kinetic bottleneck of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The application of conformational entropy strategy to oxides often involves introducing multiple elements with different properties, thereby providing outstanding bifunctional catalytic activity for OER/ORR. Nevertheless, the possible underlying catalytic pathways and potential interactions between various components are still poorly understood. This paper presents an excellent medium-entropy perovskite oxide, Sr(FeCoNiMo)1/4O3−δ (lower overpotential of 301 mV at 10 mA cm−2). Zinc-air batteries employing it as a cathode catalyst demonstrate excellent round-trip efficiency (62%). By combining theoretical calculation with experiments, we aim to establish the link between the electronic structure of perovskite oxides with different elemental compositions and their OER mechanism. Research reveals that the conformational entropy strategy can simultaneously shift the O 2p-band center and metal d-band center of perovskite oxide towards the vicinity of the Fermi energy level, thereby triggering a more favorable lattice oxygen-participated mechanism (LOM) during the OER process. The outcomes of this work provide crucial insights into the role of conformational entropy strategies in oxygen catalysis and offer potential avenues for constructing efficient and stable electrocatalysts.