Initiating cationic-anionic chemistry with stepwise surface-to-inner conversion in copper selenide superstructures for high-energy rechargeable magnesium batteries

Changliang Du, Siru He, Lifen Yang, Xin Liu, Rong Jiang, Xilan Ma, Youqi Zhu*, Meishuai Zou, Chuanbao Cao

*此作品的通讯作者

科研成果: 期刊稿件文章同行评审

4 引用 (Scopus)

摘要

Copper selenides are viewed as the most capable cathode materials for rechargeable magnesium batteries, yet suffer from unsatisfactory energy density due to their low operating voltage plateau (∼0.9 V vs. Mg/Mg2+) and insufficient reversible capacity. Herein, a stepwise conversion from surface cationic-anionic redox to inside electrochemical displacement reaction is realized in copper selenide (Cu2-xSe) superstructure cathodes. A highly reversible high-voltage platform at ∼1.6 V is discovered during discharge process. Ex-situ spectroscopy and microscopy results demonstrate that the high-voltage plateau is contributed by surface Cu2+ charge-carrier transformation and anionic Se2– redox reaction while sufficient inner Cu-Mg replacement conversion at low-voltage region. Following the favorable mechanism, the Cu2-xSe superstructure cathodes can present high specific capacity of 385.4 mAh g–1 at 0.1 A g–1 and outstanding energy density of 426.3 Wh kg–1. Moreover, the Cu2-xSe superstructure cathodes also maintain a reversible capacity of 223.6 mAh g–1 over 700 cycles with 0.0147 % capacity degradation per cycle at 1.0 A g–1 and long-term charge-discharge lifetime for 3000 cycles at 5.0 A g–1. This research reports a new Mg2+ storage mechanism for copper selenide cathodes and provides novel route to develop high-energy-density rechargeable magnesium batteries.

源语言英语
文章编号103539
期刊Energy Storage Materials
70
DOI
出版状态已出版 - 6月 2024

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