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Two‐Plateau Li‐Se Chemistry for High Volumetric Capacity Se Cathodes
Author(s) -
Qi Xiaoqun,
Yang Ying,
Jin Qiang,
Yang Fengyi,
Xie Yong,
Sang Pengfei,
Liu Kun,
Zhao Wenbin,
Xu Xiaobin,
Fu Yongzhu,
Zhou Jian,
Qie Long,
Huang Yunhui
Publication year - 2020
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.202004424
Subject(s) - electrolyte , faraday efficiency , cathode , electrode , lithium (medication) , chemical engineering , chemistry , carbonate , inorganic chemistry , materials science , organic chemistry , medicine , engineering , endocrinology
For Li‐Se batteries, ether‐ and carbonate‐based electrolytes are commonly used. However, because of the “shuttle effect” of the highly dissoluble long‐chain lithium polyselenides (LPSes, Li 2 Se n , 4≤ n ≤8) in the ether electrolytes and the sluggish one‐step solid‐solid conversion between Se and Li 2 Se in the carbonate electrolytes, a large amount of porous carbon (>40 wt % in the electrode) is always needed for the Se cathodes, which seriously counteracts the advantage of Se electrodes in terms of volumetric capacity. Herein an acetonitrile‐based electrolyte is introduced for the Li‐Se system, and a two‐plateau conversion mechanism is proposed. This new Li‐Se chemistry not only avoids the shuttle effect but also facilitates the conversion between Se and Li 2 Se, enabling an efficient Se cathode with high Se utilization (97 %) and enhanced Coulombic efficiency. Moreover, with such a designed electrolyte, a highly compact Se electrode (2.35 g Se cm −3 ) with a record‐breaking Se content (80 wt %) and high Se loading (8 mg cm −2 ) is demonstrated to have a superhigh volumetric energy density of up to 2502 Wh L −1 , surpassing that of LiCoO 2 .