聚偏氟乙烯基交联凝胶聚合物电解质的制备及性能

Preparation and Performance of Poly(vinylidene fluoride)-Based Crosslinked Gel Polymer Electrolytes

以聚偏氟乙烯(PVDF)为基体,三嵌段共聚物聚苯乙烯-聚环氧乙烷-苯乙烯(PS_(25)-PEO-PS_(25))为添加剂,通过相转化法和傅-克烷基化反应制备了超交联PVDF/PS_(25)-PEO-PS_(25)共混多孔聚合物膜(CPMs),CPMs浸泡电解液活化后得到交联凝胶聚合物电解质(CGPEs)。系统研究了PS_(25)-PEO-PS_(25)的添加量对CPMs结晶性和热稳定性以及对CGPEs电化学性能的影响。X射线衍射分析和差示扫描量热法测试结果表明,PS_(25)-PEO-PS_(25)的添加明显降低了CPMs结晶性和熔点;扫描电子显微镜测试显示,经300℃热处理后的CPMs仍保留有大量孔结构;离子电导率和充放电性能测试结果表明,当PS_(25)-PEO-PS_(25)添加量为30%时,CGPE-30%室温下的离子电导率达到最高为2.11 mS/cm,并且在0.1 C下循环50次后,容量几乎没有出现衰减,展现出优异的循环性能。

With poly(vinylidene fluoride)(PVDF)as matrix and polystyrene-b-poly(ethylene oxide)-b-polystyrene(PS25-PEO-PS25)triblock copolymers as additive,hyper-crosslinked porous polymer membranes(CPMs)were prepared by the combination of phase inversion and Friedel-Craft reaction.The CPMs were then activated by absorbing liquid electrolyte to obtain crosslinked gel polymer electrolytes(CGPEs).Then the effects of PS25-PEO-PS25 amounts on the crystallinity and thermostability of the CPMs and electrochemical performance of the CGPEs were studied.The results of X-ray diffraction and differential scanning calorimetry show that the addition of PS25-PEO-PS25 can reduce the crystallinity of CPMs effectively.And it is proved that there are still a lot of pore structures in CPMs after heat treatment at 300℃by scanning electron microscope.Furthermore,the results of ion conductivity and charge-discharge performance test show that when the addition amount of PS25-PEO-PS25 reaches 30%,GPE-30%has the highest ionic conductivity of 2.11 mS/cm at room temperature,and the capacity of GPE-30%keeps well after 50 cycles at 0.1 C,indicating its excellent cycle performance.