聚乳酸改性聚氨酯基固态电解质的制备与性能

Preparation and properties of polylactic acid modified polyurethane-based solid electrolyte

以聚乳酸二元醇(PLA)、聚氧化丙烯醚二元醇(N220)、二环己基甲烷二异氰酸酯(HMDI)、一缩二乙二醇(DECG)为原料合成一系列聚氨酯,并加入占体系质量比为20%的双三氟甲烷磺酰亚胺锂(LiTFSI),制备得到系列固态聚合物电解质(SPE),研究了PLA与N220的比例对SPE性能的影响。用傅里叶变换红外谱图表征了聚氨酯基电解质的结构;差示扫描量热分析谱图显示随着PLA质量分数的减少,SPE膜的玻璃化转变温度(Tg)减小;力学测试结果显示随着PLA质量分数的减少,SPE膜的拉伸强度逐渐下降;交流阻抗谱(EIS)和循环伏安电流法(LSV)测试结果表明,SPE膜的离子电导率与温度的关系基本符合Arrhenius方程,80℃时电化学稳定窗口达到4V以上。以PLA和N220质量比为1∶1制备的固态聚合物电解质(SPE4)综合性能最佳,拉伸强度为0.50 MPa,电化学窗口为4.2 V,离子电导率达到1.59×10^-4S/cm。

A series of polyurethane(PU)were synthesised by polylactic acid diol(PLA)and polyoxypropylene e-ther diol(N220)as the soft segment,dicyclohexylmethane diisocyanate(HMDI)and diethylene glycol(DEG)as hard segment.Solid polymer electrolytes(SPE)were prepared by adding lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)in a mass ratio of 20%in as-prepared polyurethane.The structure of the polyurethane-based electrolyte was characterized by Fourier transform infrared spectrum.The differential calorimetric scanning spectrum show that the glass transition temperature(Tg)decreases with the decrease of mass fraction of the PLA.The mechanical test resultsshow that the tensile strength of SPE film decreases with the decrease of PLA mass fraction.The resultsof electrochemical impedance spectroscopy(EIS)and linear sweep voltammetry(LSV)test indicate that the relationship between ionic conductivity and temperature is basically in accordance with the Arrhenius equation,the electrochemical stability window reaches above 4 V at 80 ℃.The solid polymer electrolyte(SPE4)prepared by m(LPA):77i(N220)=1:1 has the best comprehensive performance,the tensile strength reaches 0.50 MPa,and the i-onic conductivity was 1.59×10^-4S/cm with the electrochemical window of 4.2 V.