基于四重氢键的自修复电解质材料

Self-Healing Electrolyte Material Based on Quadruple Hydrogen Bond

为了解决锂离子电池中聚合物电解质易受外界机械损伤的问题,引入含有四重氢键的2-脲基-4[1H]嘧啶酮(Upy)单元接枝在聚乙烯醇(PVA)上,制备出具有自修复功能的电解质材料PVA-Upy,并对其结构、热稳定性以及电化学性能等进行分析。结果表明,该方法成功制备出PVA-Upy材料,其热稳定性以及机械强度良好,在70℃下拉伸强度的自修复效率达90.20%;PVA-Upy材料作为电解质的电化学窗口高达5 V,离子传导率为2.06×10−3 S/cm,组装的LiFePO4/PVA-Upy/Li扣式电池循环稳定性良好。

As a lightweight energy system,lithium ion batteries are used in different industries and fields.The electrolyte acts as a channel for ion transmission in the battery.Polymer materials are applied as electrolyte since they have the advantages of high safety,high thermal stability and high mechanical strength.However,polymer will crack in certain external environments.Thus,some researchers proposed to prepare self-healing materials and applied them to electrolyte in lithium ion battery.This work is dedicated to solve the problem that the polymer electrolyte is susceptible to mechanical damage.The preparation method of 2-ureido-4-[1H]-pyrimidinone(Upy)unit which contains the quadruple hydrogen bonds was proposed.And grafted Upy on the polyvinyl alcohol(PVA)polymer matrix was performed to prepare a self-healing electrolyte material.The chemical structure,thermal stability,self-healing ability and electrochemical performance of PVAUpy membrane were studied.The results showed that PVA-Upy material was successfully prepared by this method and proved by FT-IR and 1H-NMR measurement.PVA-Upy material showed good thermal stability and mechanical strength,and had a self-healing efficiency of 90.20%in tensile strength at 70℃.As for electrolyte,it had an electrochemical window of 5 V and its highest ion conductivity was 2.06×10−3 S/cm.Being assembled as LiFePO4/PVA-Upy/Li cell,it showed good cycle stability which suggested the application prospect in lithium ion batteries.