聚氧化乙烯固态电解质热循环结晶行为研究  

Study on the Crystallization Behavior of Polyethylene Oxide Solid Electrolyte with Thermal Cycling

作　　者：樊林 刘学清[1] FAN Lin;LIU Xueqing(Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University,Wuhan 430056,China)

机构地区：[1]江汉大学光电化学材料与器件教育部重点实验室,湖北武汉430056

出　　处：《塑料工业》2022年第10期113-119,共7页China Plastics Industry

基　　金：湖北省教育厅团队创新项目(T201935)

摘　　要：为解决现有锂离子电池的安全性问题,固态电解质的研究备受关注。通过在聚氧化乙烯(PEO)中添加不同含量的双三氟甲烷磺酰亚胺锂(LiTFSI)并进行循环加热处理,利用穆勒矩阵椭偏仪(MME)监测PEO在加热和冷却过程中的薄膜厚度以及双折射的变化,并用X射线衍射仪(XRD)、差示扫描量热分析仪(DSC)、原子力显微镜(AFM)及偏光显微镜(POM)对其结晶行为和表面进行验证。结果表明,PEO在加热和冷却时薄膜厚度和双折射值发生了明显的改变,用DSC和XRD验证发现其改变的温度对应PEO的熔融和结晶温度;添加LiTFSI的PEO薄膜熔点由64.55℃降低到59.47℃,结晶度由55.6%降低到23.1%,但是经过热循环后结晶度会增大。Solid polymer electrolytes(SPEs)had attracted considerable attention due to the rapid development of the need for more safety and powerful lithium ion batteries.In this paper,different contents of Lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)were added to poly(ethylene oxide)(PEO)and heated cyclically,and the changes of film thickness and birefringence of PEO during heating and cooling were monitored by Muller matrix ellipsometer(MME),and the crystallization behavior and surfaces were verified by X-ray diffraction(XRD),differential scanning calorimetry(DSC),atomic force microscopy(AFM)and polarizing microscope(POM).The results show that the film thickness and birefringence values of PEO films are changed significantly during heating and cooling,and the changed temperatures are verified by DSC and XRD to correspond to the melting and crystallization temperatures of PEO.After adding the LiTFSI,melting point of PEO film is reduced from 64.55℃ to 59.47℃,and the crystallinity is reduced from 55.6% to 23.1%.However,the crystallinity could increase after thermal cycling.

关 键 词：聚氧化乙烯 穆勒矩阵椭偏仪 双折射 结晶 

分 类 号：TQ317[化学工程—高聚物工业]