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

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-CeO 2 is synthetized supported on a carbon sphere (MnO-CeO 2 @Cs), adeptly crafted with a prominent work function difference (Δ Φ ) 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-CeO 2 @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-CeO 2 @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. An oxygen-deficient MnO-CeO 2 @Cs catalyst, due to its high work function and strong built-in electric field, can effectively regulate charge redistribution and adsorption/desorption energies with reaction intermediates, thereby improving ORR activity.