Open AccessA high-performance potassium metal battery using safe ionic liquid electrolyte
Author(s) -
Hao Sun,
Peng Liang,
Guanzhou Zhu,
Wei Hsuan Hung,
Yuan-Yao Li,
HungChun Tai,
Cheng Liang Huang,
Jiachen Li,
Yongtao Meng,
Michael Angell,
Chang An Wang
Publication year - 2020
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2012716117
Subject(s) - electrolyte , battery (electricity) , potassium , faraday efficiency , flammable liquid , energy storage , work (physics) , potassium ion battery , materials science , ionic liquid , metal , chemistry , environmental science , chemical engineering , electrode , metallurgy , engineering , catalysis , mechanical engineering , lithium vanadium phosphate battery , organic chemistry , power (physics) , physics , quantum mechanics
Potassium secondary batteries are contenders of next-generation energy storage devices owing to the much higher abundance of potassium than lithium. However, safety issues and poor cycle life of K metal battery have been key bottlenecks. Here we report an ionic liquid electrolyte comprising 1-ethyl-3-methylimidazolium chloride/AlCl 3 /KCl/potassium bis(fluorosulfonyl) imide for safe and high-performance batteries. The electrolyte is nonflammable and exhibits a high ionic conductivity of 13.1 mS cm -1 at room temperature. A 3.6-V battery with K anode and Prussian blue/reduced graphene oxide cathode delivers a high energy and power density of 381 and 1,350 W kg -1 , respectively. The battery shows an excellent cycling stability over 820 cycles, retaining ∼89% of the original capacity with high Coulombic efficiencies of ∼99.9%. High cyclability is also achieved at elevated temperatures up to 60 °C. Uniquely, robust K, Al, F, and Cl-containing passivating interphases are afforded with this electrolyte, which is key to superior battery cycling performances.