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

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Aprotic Li-O₂ battery has attracted considerable interest for high theoretical energy density, however the disproportionation of the intermediate of superoxide (O₂ ⁻ ) 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 O₂ ⁻ disproportionation and its kinetics in both the discharge and charge processes. RB captures O₂ ⁻ 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 O₂ ⁻ and singlet oxygen related side reactions. These endow the Li-O₂ battery with reduced discharge/charge voltage gap of 0.72 V and prolonged lifespan for over 230 cycles when coupled with RuO₂ catalyst. This work highlights the vital role of superoxide disproportionation for Li-O₂ battery.