Catalytic Disproportionation of the Superoxide Intermediate from Electrochemical O2 Reduction in Nonaqueous Electrolytes

Tris(pentafluorophenyl)borane (TPFPB) was found to be an efficient catalyst for rapid superoxide (O2−) disproportionation. The kinetics for the catalytic disproportionation reaction is much faster than the reaction between O2− and propylene carbonate. Therefore, the negative impact of the reaction between the electrolyte and O2− produced by the O2 reduction is minimized. The cathodic current for O2 reduction can be doubled in the presence of TPFPB. The high reduction current resulted from the pseudo two-electron O2-reduction reaction due to the replenishment of O2 at the electrode surface. This discovery could lead to a new avenue for the development of high-capacity, high-rate, rechargeable Li–air batteries.