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From O 2 − to HO 2 − : Reducing By‐Products and Overpotential in Li‐O 2 Batteries by Water Addition
Author(s) -
Qiao Yu,
Wu Shichao,
Yi Jin,
Sun Yang,
Guo Shaohua,
Yang Sixie,
He Ping,
Zhou Haoshen
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201611122
Subject(s) - overpotential , chemistry , electrochemistry , superoxide , battery (electricity) , gravimetric analysis , reaction mechanism , electrode , catalysis , organic chemistry , power (physics) , physics , quantum mechanics , enzyme
Abstract The development of aprotic Li‐O 2 batteries, which are promising candidates for high gravimetric energy storage devices, is severely limited by superoxide‐related parasitic reactions and large voltage hysteresis. The fundamental reaction pathway of the aprotic Li‐O 2 battery can be altered by the addition of water, which changes the discharge intermediate from superoxide (O 2 − ) to hydroperoxide (HO 2 − ). The new mechanism involving HO 2 − intermediate realizes the two‐electron transfer through a single step, which significantly suppresses the superoxide‐related side reactions. Moreover, addition of water also triggers a solution‐based pathway that effectively reduces the voltage hysteresis. These discoveries offer a possible solution for desirable Li‐O 2 batteries free of aggressive superoxide species, highlighting the design strategy of modifying the reaction pathway for Li‐O 2 electrochemistry.