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

• Published in: Chemistry : a European journal 2013-06, Vol.19 (26), p.8679-8683
• Main Authors: Zheng, Dong, Wang, Qiang, Lee, Hung-Sui, Yang, Xiao-Qing, Qu, Deyang
• Format: Article
• Language: English
• Subjects: catalytic disproportionation; Chemistry; Lewis acids; Lewis bases; lithium; reduction
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201204506

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. For a rechargeable Li–air battery an efficient catalyst for rapid superoxide (O2−) disproportionation is important. Tris(pentafluorophenyl)borane was found to catalyse the disproportionation reaction efficiently. The negative impact of the reaction between the electrolyte and O2− produced by the O2 reduction was minimized (see scheme).