交联PEO嵌段共聚物固体电解质的制备及导电性研究

利用低分子聚乙二醇 (PEG ,Mn=6 0 0 )与CH2 Cl2 在碱性条件下通过Williamson反应生成氧亚甲基连接的聚氧化乙烯嵌段聚合物 .1 H NMR表明 ,其分子平均组成以 CH2 O(CH2 CH2 O) 1 3]为重复单元结构 .适量的2 ,4 二异氰酸甲苯酯 (TDI)与聚合物 锂盐电解质形成交联网络结构 ,具有较好的成膜性能、力学性能与热稳定性能 .在测试温度范围内 ,电导率与温度的关系很好的符合Arrhenius关系式 (σ =Ae-Ea RT) .锂盐浓度不同 ,Arrhenius曲线有一个或两个活化能 (Ea)值出现 .该聚合物掺混LiN(CF3SO2 ) 2 形成的固体电解质具有良好的导电性 ,在EO Li =2 5∶1(摩尔比 )时 ,室温下σ =1 12× 10 - 5S cm ,分解电压可达 5 0V .

SYNTHESIS AND CHARACTERIZATION OF CONDUCTING CROSS-LINKED PEO BLOCK COPOLYMER ELECTROLYTES

A mixture of a low molecular weight poly(ethylene glycol) (PEG,M\-n=600) and dichloromethane (CH 2Cl 2) was polycondensated to form a block polymer.The block polymer electrolytes containing lithium salt reacted with an appropriate amount of toluene 2,4-diisocyante(TDI) to form a cross-linked polymer network,with improving the film processability,mechanical and thermal stability properties.Enhancement of the ionic conductivity and electrochemical stability of cross-linked polymer electrolyte was observed by adding lithium bis(trifluoromethane sulfonylimide) (LiN( CF 3SO 2) 2).In the range of measured temperature,the relationship between conductivity and temperature coincided with Arrhenius formula(σ=Ae -E a/RT).One or two activity energy(E\-a) values appeared in curves of Arrhenius plots with different salt concentrations.The cross-linked polymer electrolyte exhibited a high ionic conductivity of 1 12×10 -5 S/cm at room temperature, and a decomposition voltage at about 5 0?V.