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Highly Reversible Cuprous Mediated Cathode Chemistry for Magnesium Batteries
Author(s) -
Cheng Xiangyang,
Zhang Zhonghua,
Kong Qingyu,
Zhang Qinghua,
Wang Tao,
Dong Shanmu,
Gu Lin,
Wang Xiao,
Ma Jun,
Han Pengxian,
Lin Hongji,
Chen ChienTe,
Cui Guanglei
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202002177
Subject(s) - electrochemistry , cathode , electrolyte , redox , chemistry , selenide , magnesium , battery (electricity) , electrode , inorganic chemistry , copper , chemical engineering , thermodynamics , organic chemistry , power (physics) , physics , selenium , engineering
Sluggish kinetics and poor reversibility of cathode chemistry is the major challenge for magnesium batteries to achieve high volumetric capacity. Introduction of the cuprous ion (Cu + ) as a charge carrier can decouple the magnesiation related energy storage from the cathode electrochemistry. Cu + is generated from a fast equilibrium between copper selenide electrode and Mg electrolyte during standing time, rather than in the electrochemical process. A reversible chemical magnesiation/de‐magnesiation can be driven by this solid/liquid equilibrium. During a typical discharge process, Cu + is reduced to Cu and drives the equilibrium to promote the magnesiation process. The reversible Cu to Cu + redox promotes the recharge process. This novel Cu + mediated cathode chemistry of Mg battery leads to a high reversible areal capacity of 12.5 mAh cm −2 with high mass loading (49.1 mg cm −2 ) of the electrode. 80 % capacity retention can be achieved for 200 cycles after a conditioning process.