Engineering built-in electric fields in oxygen-deficient MnO-CeO2@Cs catalysts: enhanced performance and kinetics for the oxygen reduction reaction in aqueous/flexible zinc–air batteries

Abstract

Deliberate engineering of built-in electric fields (BEFs) can facilitate electron transfer and promote asymmetrical charge distribution, thereby regulating the adsorption/desorption of reaction intermediates. Herein, an oxygen-deficiency-rich MnO-CeO₂ is synthetized supported on a carbon sphere (MnO-CeO₂@Cs), adeptly crafted with a prominent work function difference (ΔΦ) and robust BEF, targeting the electrocatalytic oxygen reduction reaction (ORR). Empirical and theoretical results substantiate that the BEF triggers interfacial charge redistribution, fine-tuning the adsorption energy of oxygen intermediates and hastening reaction kinetics. Consequently, the MnO-CeO₂@Cs showcases commendable performance (E_1/2 = 0.80 V and j_L = 5.5 mA cm⁻²), outshining its single-component counterparts. Impressively, the MnO-CeO₂@Cs-based zinc–air batteries (ZABs) boast an exemplary power density of 202.7 mW cm⁻² and enduring stability of 297 h. Additionally, the solid-state ZAB commands a peak power density of 67.4 mW cm⁻², underscoring its potential in flexible ZAB applications. This work delineates a strategic avenue to harness interfacial charge redistribution, aiming to enhance the catalytic performance and longevity of energy conversion/storage apparatuses.