Effects of Li Salt and Additive Content on the Electrochemical Performance of [C4C1mim]-Based Ionic Liquid Electrolytes by Yayun Zheng Wenbin Zhou Kui Cheng & Zhengfei Chen

Author:Yayun Zheng, Wenbin Zhou, Kui Cheng & Zhengfei Chen
Format: pdf
Tags: Ionic liquids based on imidazolium cations have attracted attention due to their high safety and exceptional ionic conductivity. However, imidazole-based ionic liquids exhibit poor electrochemical stability due to the strong reactivity of hydrogen atoms at the C-2 position of imidazole cations. In this work, an ionic liquid 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ([C4C1mim][TFSA]), characterized by a methyl-substituted C-2 position and a butyl chain, was investigated in various Li+ environments created by different lithium salt concentrations and fluoroethylene carbonate (FEC) additives. Both optimal Li+ concentrations and the addition of reasonable FEC enable the improvement of ionic conductivity to 3.32 mS cm-1 at 25 C and a maximum electrochemical window of 5.21 V. The ionic liquid electrolyte Li[TFSA]-[C4C1mim][TFSA] at a molar ratio of 2:8 with 5 wt% FEC addition demonstrates excellent thermal stability. The corresponding Li/LiFePO4 cell exhibits a mitigated polarization growth (increasing from 0.12 V to 0.25 V over 10 cycles) with a high initial discharge capacity of 169.3 mAh g-1., Li+ environment; imidazolium cations; ionic liquid electrolytes; FEC additive; electrochemical stability


Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.