Octahedral distortion enhances exceptional oxygen catalytic activity of calcium manganite for advanced Zn-Air batteries

Calcium manganite (CMO) holds great potential for OER/ORR catalysis. But, the weak interaction between the oxygen intermediates and reaction sites leads to sluggish catalytic kinetics. Herein, to trigger the exceptional catalytic activity of CMO, we propose a thermal-induced MnO6 octahedral distortion strategy to advance the absorption capability of intermediate reactants. Refined structural analysis and theoretical calculation reveal that the strong Jahn-Teller distortion of MnO6 is capable of optimizing the surface electron redistribution and accelerating the electron transfer between the oxygen and Mn sites, which significantly boosts the intrinsic oxygen catalytic activities of the distorted CMO (D-CMO). Notably, the D-CMO functions as excellent bifunctional oxygen electrocatalysts and enables a high-performance solid-state Zn-air battery with satisfactory mechanical strength. Specifically, the as-assembled battery displays a remarkable open circuit voltage of 1.46 V and high peak power density of 149 mW cm-2, even outstripping noble-metal-based counterparts. Modulating the octahedral units to ignite the intrinsic oxygen catalytic activity provides enlightening clues to design perovskitetype air cathodes.

Automated summary

Through a thermal-induced MnO6 octahedral distortion strategy, the surface electron redistribution of calcium manganite is optimized, accelerating the electron transfer between oxygen and manganese sites, significantly enhancing the oxygen catalytic activities.