Revealing instability and irreversibility in nonaqueous sodium–O₂ battery chemistry

Abstract

Charging kinetics and reversibility of Na-O2 batteries can be influenced greatly by the particle size of NaO2 formed upon discharge, and exposure time (reactivity) of NaO2 to the electrolyte. Micrometer-sized NaO2 cubes formed at high discharge rates were charged at smaller overpotentials compared to nanometer-sized counterparts formed at low rates.