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Initiating a Room‐Temperature Rechargeable Aqueous Fluoride‐Ion Battery with Long Lifespan through a Rational Buffering Phase Design
Author(s) -
Li Xuejin,
Tang Yongchao,
Zhu Jiaxiong,
Lv Haiming,
Xu Yan,
Wang Wenlong,
Zhi Chunyi,
Li Hongfei
Publication year - 2021
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202003714
Subject(s) - electrolyte , materials science , electrochemistry , battery (electricity) , fluoride , aqueous solution , dissolution , ion , phase (matter) , electrode , chemical engineering , inorganic chemistry , chemistry , organic chemistry , thermodynamics , power (physics) , physics , engineering
Previously reported fluoride‐ion batteries (FIBs) can only work at high temperatures (>150 °C) with solid electrolytes or organic electrolytes. Aqueous FIB has barely been reported due to the unstable F – electrochemistry in aqueous electrolytes. In addition, the electrode materials commonly suffer from serious and adverse volume expansion during the conversion reaction. Herein, a stable aqueous F – electrochemistry is realized by a rational buffering phase design in which stagger distribution of BiF 3 and Bi 7 F 11 O 5 phases is achieved. The enhanced F – electrochemistry is systematically studied and suggests that the Bi 7 F 11 O 5 phase plays a vital role in the stability and reversibility of the electrode due to its lower volume change and higher electronic conductivity. Pulverization and dissolution of active species issues are also suppressed. As a result, the assembled battery delivers excellent cycling stability, high reversibility, and superior rate capability, which is far better than conventional solid fluoride shuttle batteries. Mechanism studies demonstrate that the capacity comes from reversible conversion between Bi 3+ and Bi 0 with an intermediate phase of Bi 7 F 11 O 5 . This work initiates room‐temperature FIBs with aqueous electrolytes and provides a good cycling lifespan, which pave the way to a more practical fluoride ion storage system.