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Reversible Oxygen Redox Chemistry in Aqueous Zinc‐Ion Batteries
Author(s) -
Wan Fang,
Zhang Yan,
Zhang Linlin,
Liu Daobin,
Wang Changda,
Song Li,
Niu Zhiqiang,
Chen Jun
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201902679
Subject(s) - redox , electrolyte , aqueous solution , cathode , energy storage , oxygen evolution , oxygen , chemical engineering , inorganic chemistry , chemistry , oxygen storage , electrochemistry , materials science , electrode , organic chemistry , thermodynamics , power (physics) , physics , engineering
Rechargeable aqueous zinc‐ion batteries (ZIBs) are promising energy‐storage devices owing to their low cost and high safety. However, their energy‐storage mechanisms are complex and not well established. Recent energy‐storage mechanisms of ZIBs usually depend on cationic redox processes. Anionic redox processes have not been observed owing to the limitations of cathodes and electrolytes. Herein, we describe highly reversible aqueous ZIBs based on layered VOPO 4 cathodes and a water‐in‐salt electrolyte. Such batteries display reversible oxygen redox chemistry in a high‐voltage region. The oxygen redox process not only provides about 27 % additional capacity, but also increases the average operating voltage to around 1.56 V, thus increasing the energy density by approximately 36 %. Furthermore, the oxygen redox process promotes the reversible crystal‐structure evolution of VOPO 4 during charge/discharge processes, thus resulting in enhanced rate capability and cycling performance.