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

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

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SiO_2和PVA接枝改性,并加入不同锂盐,制备了SiO_2-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SiO_2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(Tg)大幅度下降;LiClO_4在基体中的离解能力强于Li CF_3SO_3和Li N(SO_3CF_3)_2;当Li CF3SO3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2.58×10-6S·cm-1.

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（SiO_2） and polyving akohol（PVA）. And different lithium salts were added to fabricate the SiO_2-g-HBPAE/PVA-g-HBPAE hyperbrandched/comb-like composite polymer electrolytes（CPEs）. The dis persion 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 between SiO_2 and matrix. Sulfonic acid type lithium salts accelerated self-plasticizing with the Tgvalues being decreased. The LiClO_4 manifested stronger solubility than Li CF3SO3 and Li N（SO3CF3）2in the polymer matrices. The ionic conductivity of the polymer electrolytes reached the maximum value of 2.58 × 10-6S·cm-1after the addition of 20% Li CF3SO3 at room temperature.