Recovering the electrochemical window by forming a localized solvation nanostructure in ionic liquids with trace water  

作　　者：Jianing Meng Meng Ye Yue Wang Yinglun Sun Xu Zhang Kaiyuan Shi Xingbin Yan 

机构地区：[1]School of Materials Science and Engineering,Sun Yat-Sen University,Guangzhou 510275,China [2]Laboratory of Clean Energy Chemistry and Materials,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China [3]School of Petrochemical Engineering,Lanzhou University of Technology,Lanzhou 730050,China [4]School of Physical Science and Technology,Lanzhou University,Lanzhou 730000,China

出　　处：《Science China Chemistry》2022年第1期96-105,共10页中国科学（化学英文版）

基　　金：supported by the Zhaoqing Municipal Science and Technology Bureau(2019K038);the Research Start-up Funds from Sun Yat-sen University。

摘　　要：Motivated by the fascinating merits of wide electrochemical stability window(ESW)and nonflammability,ionic liquids(ILs)have been utilized as advanced electrolytes in various emerging electrochemical energy storage technologies.However,ILs are hygroscopic to the water in the air and the presence of trace water will narrow the ESW of ILs.In this article,we report that a localized solvation nanostructure(LSNS)is formed in ILs,which plays an important role in fully recovering the originally decreased ESW of[EMIM][TFSI]IL owing to the trace water.Such LSNS is consisted of Li^(+)ions with water molecules as the center,TFSI-anions as the secondary periphery and EMIM^(+)cations as the outermost layer after adding the proper amount of LiTFSI.This nanostructure can restrain the possibility of trace water to approach the electrode/electrolyte interfaces and adverse redox reactions,thereby recovering the ESW.Moreover,the effectiveness of this strategy in different kinds of ILs to fully recover ESW decreasing is verified.This article comes up with a feasible method to eliminate the trace water caused ESW drop for ILbased electrolytes and provides a new insight for understanding the molecular-level interaction between different ions in ILs with water molecules.

关 键 词：SUPERCAPACITOR ionic liquid electrochemical window lithium salt trace water 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O645.1[理学—物理化学] TM53[理学—化学]