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High‐Performance MnO 2 /Al Battery with In Situ Electrochemically Reformed Al x MnO 2 Nanosphere Cathode
Author(s) -
Pan Wending,
Mao Jianjun,
Wang Yifei,
Zhao Xiaolong,
Leong Kee Wah,
Luo Shijing,
Chen Yue,
Leung Dennis Y. C.
Publication year - 2021
Publication title -
small methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.66
H-Index - 46
ISSN - 2366-9608
DOI - 10.1002/smtd.202100491
Subject(s) - cathode , electrochemistry , materials science , battery (electricity) , electrolyte , energy storage , current density , electrolysis , anode , chemical engineering , high voltage , electrode , voltage , chemistry , electrical engineering , power (physics) , physics , quantum mechanics , engineering
Aqueous Al–ion battery (AAIB) is regarded as a promising candidate for large‐scale energy storage systems due to its high capacity, high safety, and low cost, with MnO 2 proved to be a high‐performance cathode. However, the potential commercial application of this type of battery is plagued by the frequent structural collapse of MnO 2 . Herein, an in situ, electrochemically reformed, urchin‐like Al x MnO 2 cathode is developed for water‐in‐salt electrolyte‐based AAIBs. Benefiting from its unique α‐MnO 2 coated Mn 2 AlO 4 structure, a high Al ion storage capacity is achieved together with a high discharge voltage plateau of 1.9 V by reversible MnO 2 electrolysis. Consequently, the battery exhibits a high specific capacity of 285 mAh g –1 and a high energy density of 370 Wh kg –1 at a high current density of 500 mA g –1 . Improved stability with record capacity retention is also obtained at an ultrahigh current density of 5 A g –1 after 500 cycles. Such a high‐capacity and high‐stability Al x MnO 2 cathode would pave the way for in situ electrochemical transformation of cathode design and thus boost the practical application of AAIBs.