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Toward Flexible Zinc‐Ion Hybrid Capacitors with Superhigh Energy Density and Ultralong Cycling Life: The Pivotal Role of ZnCl 2 Salt‐Based Electrolytes
Author(s) -
Wang Cheng,
Pei Zengxia,
Meng Qiangqiang,
Zhang Chunmei,
Sui Xiao,
Yuan Ziwen,
Wang Sijie,
Chen Yuan
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202012030
Subject(s) - electrolyte , materials science , power density , energy storage , battery (electricity) , capacitor , zinc , supercapacitor , density functional theory , ion , chemical engineering , electrode , electrochemistry , nanotechnology , chemistry , voltage , power (physics) , electrical engineering , computational chemistry , metallurgy , thermodynamics , physics , organic chemistry , engineering
Zinc ion hybrid capacitors (ZIHCs) are promising energy storage devices for emerging flexible electronics, but they still suffer from trade‐off in energy density and cycling life. Herein, we show that such a dilemma can be well‐addressed by deploying ZnCl 2 based electrolytes. Combining experimental studies and density functional theory (DFT) calculations, for the first time, we demonstrate an intriguing chloride ion (Cl − ) facilitated desolvation mechanism in hydrated [ZnCl] + (H 2 O) n−1 (with n=1–6) clusters. Based on this mechanism, a water‐in‐salt type hydrogel electrolyte filled with ZnCl 2 was developed to concurrently improve the energy storage capacity of porous carbon materials and the reversibility of Zn metal electrode. The resulting ZIHCs deliver a battery‐level energy density up to 217 Wh kg −1 at a power density of 450 W kg −1 , an unprecedented cycling life of 100 000 cycles, together with excellent low‐temperature adaptability and mechanical flexibility.