原位热聚合制备PVC-SN共混固态电解质及其性能  

Preparation and properties of PVC-SN solid-state electrolyte via in-situ thermal polymerization

作　　者：陈敏健 张思玉 马骋 韦伟峰[1] CHEN Minjian;ZHANG Siyu;MA Cheng;WEI Weifeng(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2021年第2期139-146,共8页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(51971250)。

摘　　要：固态电解质的低离子电导率和不稳定的电解质/电极界面是阻碍固态锂电池发展的关键问题。本文采用原位热聚合法制备聚碳酸亚乙烯酯(PVC)和丁二腈(SN)共混固态电解质,研究SN对PVC固态电解质本征性能以及固态电解质/电极界面稳定性的影响。研究结果表明:具有较好抗氧化性的SN均匀地分布在固态电解质内部,促进锂盐解离的同时提高聚合物链段运动能力,实现对离子导电网络的增强。引入SN后,室温离子电导率从2.4×10^(−6) S/cm提升至1.213×10^(−3) S/cm,氧化分解电位从4.58 V提升至5.52 V。当w(SN)为10%时展现出优异的循环稳定性,放电比容量高达163.1 mAh/g。在充电过程中,SN上具有孤电子对的氰基与高活性过渡金属离子配位络合,可减少电解质/电极界面副反应,提高正极材料的结构稳定性。The low ion conductivity of solid-state electrolyte and instable electrode-electrolyte interface are key factors to hindering the development of solid-state lithium battery.In this work,we synthesized a novel solid-state electrolyte combined poly(vinylene carbonate)and succinonitrile(SN)via in-situ thermal polymerization,and studied the effect of SN on solid-state electrolyte electrochemical properties and electrode-electrolyte interface.The results show that the high antioxidative SN are uniformly distributed in the solid-state electrolyte,which promotes the dissociation of lithium salts as well as the movement ability of polymer segments and hence enhances the network of ionic conductivity.After the introduction of SN,the ionic conductivity at room temperature increases from 2.4×10^(−6) S/cm to 1.213×10^(−3) S/cm,and the decomposition potential increases from 4.58 V to 5.52 V.The solid-state electrolyte with w(SN)=10%delivers excellent cyclability with a high discharge capacity of 163.1 mAh/g.During the charging process,the nitrile group with lone pair electrons on the SN can coordinate with the highly reactive transition metal ions,which suppresses the parasitic reactions on the electrode-electrolyte interface and thus enhances the structural stability of cathode materials.

关 键 词：固态电解质 锂电池 离子电导率 电解质/电极界面 放电比容量 

分 类 号：TM912[电气工程—电力电子与电力传动]