The origin of potential rise during charging of Li-O2 batteries

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2017,（12）
• 页码范围: 1527-1532
• 页数: 6页
• 语种: 英文
• DOI: 10.1007/s11426-017-9085-5

摘要

When aprotic Li-O2 batteries recharge,the solid Li2O2 in the positive electrode is oxidized,which often exhibits a continuous or step increase in the charging potential as a function of the charging capacity,and its origin remains incompletely understood.Here,we report a model study of electro-oxidation of a Li2O2 film on an Au electrode using voltammetry coupled with in situ Raman spectroscopy.It was found that the charging reaction initializes at the positive electrode|Li2O2 interface,instead of the previously presumed Li2O2 surface,and consists of two temporally and spatially separated Li2O2 oxidation processes,accounting for the potential rise during charging of Li-O2 batteries.Moreover,the electrode surface-initialized oxidation can disintegrate the Li2O2 film resulting in a loss of Li2O2 into electrolyte solution,which drastically decreases the charging efficiency and highlights the importance of using soluble electro-catalyst for the complete charging of Li-O2 batteries.