Porous perovskite calcium–manganese oxide microspheres as an efficient catalyst for rechargeable sodium–oxygen batteries

Abstract

We report herein the preparation of porous CaMnO₃ microspheres and their electrochemical catalytic performance as a cathode for rechargeable sodium–oxygen (Na–O₂) batteries. In ether-based electrolytes, the CaMnO₃/C cathode exhibits a high discharge capacity of 9560 mA h g⁻¹ at a current density of 100 mA g⁻¹, high rate capability (a capacity of 1940 mA h g⁻¹ at 1000 mA g⁻¹), and considerable cyclability up to 80 cycles. Two discharged species of NaO₂ and Na₂O₂ are detected at the discharged state. The remarkable electrocatalytic activity of CaMnO₃ both for the oxygen reduction reaction (ORR) and for the oxygen evolution reaction (OER) is attributed to the porous micro–nanostructures in stable ether-based electrolytes.