不同锂盐对超支化/梳状复合型聚合物电解质的性能影响研究

利用PVA侧链上的羟基的化学活性, 采用超支化聚胺-酯对改性纳米SiO₂和PVA接枝改性, 并加入不同锂盐，制备了SiO₂-g-HBPAE/PVA-g-HBPAE超支化/梳状复合型聚合物电解质, 利用SEM观察了纳米粒子在基体中的分散情况, 采用DSC、拉伸实验以及介电谱研究了锂盐种类及添加量对复合体系性能的影响. 结果表明, 超支化接枝改善了SiO₂和基体的界面相容性; 磺酸类锂盐在复合材料中表现出自增塑现象, 材料的玻璃化转变温度(T_g)大幅度下降; LiClO₄在基体中的离解能力强于LiCF₃SO₃和 LiN(SO₃CF₃)₂; 当LiCF₃SO₃添加量为20 %(by mass, 下文同)时, 聚合物电解质的室温电导率达到最大值2.58×10^-6 S•cm^-1.

Effects of Lithium Salts on the Properties of Hyperbrandched/Comb-like Composite Polymer Electrolytes

Based on the chemical characteristics of the hydroxyl group of PVA side-chain, the hyperbrandched poly(amine-ester) (HBPAE) was used to hypergraftingly pretreated nano-silica (SiO₂) and polyving akohol (PVA). And different lithium salts were added to fabricate theSiO₂-g-HBPAE/PVA-g-HBPAE hyperbrandched/comb-like composite polymer electrolytes (CPEs). The dispersion of nanoparticles in matrix was observed by SEM. The effects of different lithium salts on the properties of CPEs were studied by DSC, tensile test and dielectric spectra. The results showed that the hypergrafting method improved the interphase compatibility betweenSiO₂ and matrix. Sulfonic acid type lithium salts accelerated self-plasticizing with the Tg values being decreased. The LiClO₄ manifested stronger solubility thanLiCF₃SO₃ andLiN(SO₃CF₃)₂ in the polymer matrices. The ionic conductivity of the polymer electrolytes reached the maximum value of 2.58×10^-6 S·cm^-1 after the addition of 20%LiCF₃SO₃ at room temperature.