New Reaction Pathway of Superoxide Disproportionation Induced by a Soluble Catalyst in Li‐O2 Batteries

Abstract Aprotic Li‐O 2 battery has attracted considerable interest for high theoretical energy density, however the disproportionation of the intermediate of superoxide (O 2 − ) during discharge and charge leads to slow reaction kinetics and large voltage hysteresis. Herein, the chemically stable ruthenium tris(bipyridine) (RB) cations are employed as a soluble catalyst to alternate the pathway of O 2 − disproportionation and its kinetics in both the discharge and charge processes. RB captures O 2 − dimer and promotes their intramolecular charge transfer, and it decreases the energy barrier of the disproportionation reaction from 7.70 to 0.70 kcal mol −1 . This facilitates the discharge and charge processes and simultaneously mitigates O 2 − and singlet oxygen related side reactions. These endow the Li‐O 2 battery with reduced discharge/charge voltage gap of 0.72 V and prolonged lifespan for over 230 cycles when coupled with RuO 2 catalyst. This work highlights the vital role of superoxide disproportionation for Li‐O 2 battery.