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Unraveling the Nature of Excellent Potassium Storage in Small‐Molecule Se@Peapod‐Like N‐Doped Carbon Nanofibers
Author(s) -
Xu Rui,
Yao Yu,
Wang Haiyun,
Yuan Yifei,
Wang Jiawei,
Yang Hai,
Jiang Yu,
Shi Pengcheng,
Wu Xiaojun,
Peng Zhangquan,
Wu ZhongShuai,
Lu Jun,
Yu Yan
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202003879
Subject(s) - materials science , battery (electricity) , electrochemistry , electrolyte , microporous material , cathode , anode , molecule , chemical engineering , nanofiber , energy storage , nanotechnology , carbon nanofiber , carbon fibers , potassium ion battery , electrode , organic chemistry , carbon nanotube , chemistry , composite number , power (physics) , physics , quantum mechanics , engineering , composite material , lithium vanadium phosphate battery
The potassium–selenium (K–Se) battery is considered as an alternative solution for stationary energy storage because of abundant resource of K. However, the detailed mechanism of the energy storage process is yet to be unraveled. Herein, the findings in probing the working mechanism of the K‐ion storage in Se cathode are reported using both experimental and computational approaches. A flexible K–Se battery is prepared by employing the small‐molecule Se embedded in freestanding N ‐doped porous carbon nanofibers thin film (Se@NPCFs) as cathode. The reaction mechanisms are elucidated by identifying the existence of short‐chain molecular Se encapsulated inside the microporous host, which transforms to K 2 Se by a two‐step conversion reaction via an “all‐solid‐state” electrochemical process in the carbonate electrolyte system. Through the whole reaction, the generation of polyselenides (K 2 Se n , 3 ≤ n ≤ 8) is effectively suppressed by electrochemical reaction dominated by Se 2 molecules, thus significantly enhancing the utilization of Se and effecting the voltage platform of the K–Se battery. This work offers a practical pathway to optimize the K–Se battery performance through structure engineering and manipulation of selenium chemistry for the formation of selective species and reveal its internal reaction mechanism in the carbonate electrolyte.