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ZnCl 2 “Water‐in‐Salt” Electrolyte Transforms the Performance of Vanadium Oxide as a Zn Battery Cathode
Author(s) -
Zhang Lu,
RodríguezPérez Ismael A.,
Jiang Heng,
Zhang Chong,
Leonard Daniel P.,
Guo Qiubo,
Wang Wenfeng,
Han Shumin,
Wang Limin,
Ji Xiulei
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201902653
Subject(s) - electrolyte , cathode , materials science , battery (electricity) , energy storage , vanadium , aqueous solution , chemical engineering , inorganic chemistry , current density , electrode , metallurgy , chemistry , power (physics) , physics , quantum mechanics , engineering
Zn batteries potentially offer the highest energy density among aqueous batteries that are inherently safe, inexpensive, and sustainable. However, most cathode materials in Zn batteries suffer from capacity fading, particularly at a low current rate. Herein, it is shown that the ZnCl 2 “water‐in‐salt” electrolyte (WiSE) addresses this capacity fading problem to a large extent by facilitating unprecedented performance of a Zn battery cathode of Ca 0.20 V 2 O 5 ∙0.80H 2 O. Upon increasing the concentration of aqueous ZnCl 2 electrolytes from 1 m to 30 m, the capacity of Ca 0.20 V 2 O 5 ∙0.80H 2 O rises from 296 mAh g −1 to 496 mAh g −1 ; its absolute working potential increases by 0.4 V, and most importantly, at a low current rate of 50 mA g −1 , that is, C/10; its capacity retention increases from 8.4% to 51.1% over 100 cycles. Ex situ characterization results point to the formation of a new ready‐to‐dissolve phase on the electrode in the dilute electrolyte. The results demonstrate that the Zn‐based WiSE may provide the underpinning platform for the applications of Zn batteries for stationary grid‐level storage.