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Highly Concentrated KTFSI : Glyme Electrolytes for K/Bilayered‐V 2 O 5 Batteries
Author(s) -
Liu Xu,
Elia Giuseppe Antonio,
Gao Xinpei,
Qin Bingsheng,
Zhang Huang,
Passerini Stefano
Publication year - 2020
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.202000003
Subject(s) - electrolyte , materials science , potassium , electrode , dissolution , anode , chemical engineering , inorganic chemistry , chemistry , metallurgy , engineering
Highly concentrated glyme‐based electrolytes are friendly to a series of negative electrodes for potassium‐based batteries, including potassium metal. However, their compatibility with positive electrodes has been rarely explored. In this work, the influence of the molar fraction of potassium bis(trifluoromethanesulfonyl)imide dissolved in glyme on the cycling ability of K/bilayered‐V 2 O 5 batteries has been investigated. At high salt concentration, the interaction between K + ions with the glyme is strengthened, leading to a limited number of free glyme molecules. Therefore, the anodic decomposition of the electrolyte solvent, as well as the dissolution of the Al current collectors, is effectively suppressed, resulting in the improved cycling ability of the K/bilayered‐V 2 O 5 cells. In these cells, the positive electrode active material exhibits reversible capacities of 93 and 57 mAh g −1 at specific current densities of 50 and 1000 mA g −1 , respectively. After 200 charge‐discharge cycles at 500 mA g −1 , the cell retains 94 % of the initial capacity. The promising rate performance and capacity retention demonstrate the importance of proper electrolyte engineering for the K/bilayered‐V 2 O 5 batteries, and the good compatibility of highly concentrated glyme‐based electrolytes with positive electrode materials for potassium batteries.