Transport of Propylene Carbonate-LiTFSI Electrolytes in P(VDF-HFP)Using Time-resolved ATR-FTIR Spectroscopy:Diffusion Coefficients and Molecular Interactions

作     者：Hui-Xian Li Lei Hou Pei-Yi Wu Hui-Xian Li;Lei Hou;Pei-Yi Wu

作者机构：National Engineering Research Center for Dyeing and Finishing of TextilesCollege of ChemistryChemical Engineering and BiotechnologyDonghua UniversityShanghai 201620China 

出 版 物：《Chinese Journal of Polymer Science》 (高分子科学（英文版）)

年 卷 期：2021年第39卷第8期

页      面：975-983,I0005页

核心收录：

学科分类：0808[工学-电气工程] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070302[理学-分析化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 

基　　金：the National Natural Science Foundation of China(No.21803010,21991123 and 51733003) the Shanghai Sailing Program(No.18FY1401100). 

主　　题：ATR-FTIR spectroscopy Gel polymer electrolyte Transport mechanism Molecular interaction Diffusion coefficient 

摘      要：The time-resolved attenuated total reflectance-Fourier transform infrared(ATR-FTIR)spectroscopy is employed to investigate the transport mechanism of gel electrolytes by monitoring the diffusion behavior of propylene carbonate-lithium bis(trifluoromethylsulfonyl)imide(PC-LiTFSI)solution through poly(vinylidene fluoride-co-hexafluoropropylene)(P(VDF-HFP))films.Fickian behavior has been observed for both TFSr and PC.Higher temperature leads to faster diffusion of TFSI and PC,which could be related to the increased free volume in P(VDF-HFP)matrix and rapid molecular movements upon heating.Various molecular interactions among LiTFSI,PC and P(VDF-HFP)have been recognized.During the diffusion process,PC molecules,in the form of small clusters,can firstly diffuse through the P(VDF-HFP)film and interact with P(VDF-HFP)by dipole-dipole interaction,acting as the plasticizer.Then,Li+diffuses into P(VDF-HFP)with the help of ion-dipole interactions between Li+and C=0 of PC.Meanwhile,TFSI-diffuses through the polymer matrix in solvation states.In addition,slight ion-dipole interactions between Li+and P(VDF-HFP)have been observed as well.Results in this work contribute to a better understanding of transport process in gel polymer electrolytes for lithium-ion batteries and support the development of improved gel polymer electrolytes by rationally regulating molecular interactions.