Copolymer-assisted Polypropylene Separator for Fast and Uniform Lithium Ion Transport in Lithium-ion Batteries  

作　　者：Yan Yan Qing-Ran Kong Chuang-Chao Sun Jia-Jia Yuan Zheng Huang Li-Feng Fang Bao-Ku Zhua You-Zhi Song 

机构地区：[1]Key Laboratory of Macromolecule Synthesis and Functionalization(Ministry of Education),ERC of Membrane and Water Treatment(Ministry of Education),Department of Polymer Science and Engineering,Zhejiang University,Hangzhou 310027,China [2]Institute ofNuclear and New Energy Technology,Tsinghua University,Beijing W0084,China

出　　处：《Chinese Journal of Polymer Science》2020年第12期1313-1324,共12页高分子科学（英文版）

基　　金：supported by the National 863 Program of China(No.2012AA03A602);National Key R&D Program of China(No.2017YFE0114100);Science and Technology Project of Guangdong Province of China(No.2019 ST115);the National Natural Science Foundation of China(No.21805240).

摘　　要：In lithium-ion batteries(LIBs),separators play a vital role in lithium-ion(Li+)transport,and thus affect rate performance,battery life,and safety.Here,a new kind of multifunctional copolymer poly(acrylonitrile-co-lithium acrylate-co-butyl acrylate)(PAAB-Li)is synthesized through soap-free emulsion polymerization,and is used to form homogeneous-covered separator based on PP matrix by a simple dip-annealing process.Compared to the bare PP separator,the modified separators with PAAB-Li enable higher ionic conductivity,higher lithium ion transference number(increased from 0.360 to 0.525),and lower interface impedance(reduced from 155Ω to 34Ω).It has been indicated that PAAB-Li functional layer significantly promotes the fast transport of Li+and improves the compatibility of the separator/electrolyte-electrode interface.The LiCo02/graphite cells with the PAAB-Li-assisted separator demonstrate excellent cycle stability and rate performance.In addition,the Li symmetric cells with the modified separator stably cycle over 800 h,indicating the functional layer effectively suppresses the lithium dendrite growth.This facile strategy can be easily applied to LIBs requiring high safety and even be scalable to Li metal batteries.Moreover,the possible mechanism of the PAAB-Li functional layer promoting fast and uniform Li+transport is discussed in this paper.

关 键 词：Polyelectrolytes Polypropylene separator Lithium ion transport Dendrite-free Lithium-ion battery 

分 类 号：TM912[电气工程—电力电子与电力传动] TB383.2[一般工业技术—材料科学与工程]