La0.75Sr0.25MnO3-based perovskite oxides as efficient and durable bifunctional oxygen electrocatalysts in rechargeable Zn-air batteries [La0.75Sr0.25MnO3基钙钛矿氧化物作为可充电锌空气电池中高效耐用的双功能氧电催化剂]

Efficient and durable bifunctional oxygen electrocatalysts are critical for advanced rechargeable zinc-air (Zn-air) batteries. However, the obstacle to the development of bifunctional electrocatalysts for the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) lies in the different requirements of the ORR and OER for catalytic materials. Herein, La _0.75Sr _0.25Mn _0.5X _0.5O ₃ (X = Co, Ni, and Fe) perovskite nanoparticles were created by rationally screening targeted ORR/OER components and precisely controlling their electronic structures to achieve bifunctional oxygen electrocatalysis, in which La _0.75Sr _0.25Mn _0.5Fe _0.5O ₃ (LSFMO) displayed superior ORR performance (E _onset of 0.932 V and n of 3.59) and significantly enhanced electrocatalytic activity in the OER process (an E _j=10 of 1.658 V and overpotential of 428 mV), corresponding to excellent bifunctional properties (ΔE = 0.94 V). Furthermore, density functional theory (DFT) calculations demonstrated that Mn and Fe dual sites generated by partial substitution had a significant synergistic effect on the electrocatalytic process. The rechargeable Zn-air batteries delivered an unprecedented small charge-discharge voltage polarization (0.76 V), high reversibility and stability over many charge-discharge cycles (60 h). These excellent results demonstrate that Mn-based perovskites with Fe doping are undoubtedly promising bifunctional electrocatalysts for rechargeable Zn-air batteries. [Figure not available: see fulltext.].