Understanding fluorine-free electrolytes via small-angle X-ray scattering  

作　　者：Kun Qian Zhou Yu Yuzi Liu David J.Gosztola Randall E.Winans Lei Cheng Tao Li 

机构地区：[1]Department of Chemistry and Biochemistry,Northern Illinois University,DeKalb,IL 60115,USA [2]Materials Science Division and Joint Center for Energy Storage Research,Argonne National Laboratory,Lemont,IL 60439,USA [3]Center for Nanoscale Materials,Argonne National Laboratory,Lemont,IL 60439,USA [4]X-ray Science Division and Joint Center for Energy Storage Research,Argonne National Laboratory,Lemont,IL 60439,USA

出　　处：《Journal of Energy Chemistry》2022年第7期340-346,I0009,共8页能源化学（英文版）

基　　金：supported as part of the Joint Center for Energy Storage Research,an Energy Innovation Hub funded by the U.S.Department of Energy,Office of Science,Basic Energy Sciences;the supported by U.S.National Science Foundation(Grant No.2120559);。

摘　　要：Fluorine-free electrolytes have attracted great attention because of its low-cost and environmental friendliness. However, so far, little is known about the solution structures of these electrolytes. Here,we compare the solvation phenomenon of sodium tetraphenylborate(NaBPh_(4)) salt dissolved in organic solvents of propylene carbonate(PC), 1,2-dimethoxyethane(DME), acetonitrile(ACN) and tetrahydrofuran(THF). Small-angle X-ray scattering(SAXS) reveals a unique two-peak structural feature in this saltconcentrated PC electrolyte, while solutions using other solvents only have one scattering peak.Molecular dynamics(MD) simulations further reveal that there are anion-based clusters in addition to the short-range charge ordering in the concentrated NaBPh4/PC electrolyte. Raman spectroscopy confirms the existence of considerable contact ion pairs(CIPs). This work emphasizes the importance of global and local structural analysis, which will provide valuable clues for understanding the structureperformance relationship of electrolytes.

关 键 词：Fluorine-free electrolytes Sodium-ion batteries Small-angle X-ray scattering Solvation structures Sodium tetraphenylborate 

分 类 号：TM912[电气工程—电力电子与电力传动] O646[理学—物理化学]