嵌段共聚物电解质的制备及其电化学性能  

Preparation of block copolymer electrolytes and its electrochemical performance

作　　者：张锟 刘娜 田君 梁晓嫱 陈光海 高洪波[1] 胡道中[1] 佟蕾[1] 田崔钧[1] 王浩辰 ZHANG Kun;LIU Na;TIAN Jun;LIANG Xiaoqiang;CHEN Guanghai;GAO Hongbo;HU Daozhong;TONG Lei;TIAN Cuijun;WANG Haochen(China North Vehicle Research Institute,Beijing 100072,China;Beijing WELION New Energy Technology Co.,Ltd.,Beijing 102402,China)

机构地区：[1]中国北方车辆研究所,北京100072 [2]北京卫蓝新能源科技有限公司,北京102402

出　　处：《材料工程》2024年第6期69-77,共9页Journal of Materials Engineering

基　　金：国家自然科学基金项目(22209156,52075028)。

摘　　要：通过设计聚合物分子结构,采用热引发自由基聚合方法合成聚乙二醇甲醚甲基丙烯酸酯(PEGMEMA)和甲基丙烯酸缩水甘油酯(GMA)的二嵌段共聚物电解质PEGMEMAm-GMAn-Br(PGA-Br),并研究其电化学性能。结果表明:将PGA嵌段或接枝到聚合物电解质上,可提高聚合物电解质的离子电导率,室温下的离子电导率达1.05×10^(−4)S·cm^(−1)。同时,PGA-Br嵌段共聚物电解质具有较低的玻璃化转变温度(-65℃)、较高的热分解温度、较宽的电化学稳定窗口(5.1 V)和阻燃特性。PGA-Br共聚物电解质组装下的固态Li|Li对称电池具有增强的电极/电解质固-固界面,可实现金属锂均匀沉积,有效抑制锂枝晶的生长。在0.1 C倍率下,基于PGA-Br嵌段共聚物电解质组装的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)|PGA-Br|Li固态全电池可实现较高的首周放电比容量(160.1 mAh·g^(−1)),且循环100周次后容量保持率高达91.5%,库仑效率稳定在98.5%以上。The diblock copolymer electrolyte PEGMEMAm-GMAn-Br(PGA-Br),a copolymer of poly(ethylene glycol methyl ether methacrylate)(PEGMEMA),and glycidyl methacrylate(GMA)were synthesised by designing the molecular structure of the polymer and using thermally-initiated free-radical polymerisation.The electrochemical performance were investigated.The results show that the ionic conductivity of polymer electrolyte is improved by PGA block or grafting on polymer electrolyte,and the ionic conductivity at room temperature reaches 1.05×10^(−4)S·cm^(−1).At the same time,PGA-Br block copolymer electrolytes exhibit a low glass transition temperature(-65℃),a high thermal decomposition temperature,an electrochemical stability window of up to 5.1 V,and flame-retardant property.The Li|Li symmetrical solid-state battery assembled with PGA-Br copolymer electrolyte exhibits an enhanced electrode/electrolyte solid-solid interface,which can achieve uniform deposition of lithium metal and effectively inhibit the lithium dendrites growth.The LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)|PGA-Br|Li solid-state battery based on PGA-Br block copolymer electrolyte can achieve a high first cycle discharge specific capacity of 160.1 mAh/g at 0.1 C,and the capacity retention rate is as high as 91.5%after 100 cycles,and with a stable Coulombic efficiency of over 98.5%.

关 键 词：固态锂金属电池 嵌段共聚物电解质 锂金属负极 锂枝晶 热引发聚合 

分 类 号：TQ028.1[化学工程]