ETPTA复合PVDF-HFP基聚合物固态电解质膜的制备与性能研究

Preparation and properties of ETPTA composite PVDF-HFP-based polymer solid electrolyte membrane

固态电池因其优异的性能备受关注,但是与传统的液态电池相比,离子传输能力偏弱,原因是固-固界面离子传输困难。本文制备了以聚偏氟乙烯-六氟丙烯(PVDF-HFP)为基的固态电解质膜,并探究PVDF-HFP和增塑剂乙氧基化三羟甲基丙烷三丙烯酸酯(ETPTA)质量比为1.0∶0.3、1.0∶0.4、1.0∶0.5时对电解质膜离子传输的影响,并组装成以磷酸铁锂为正极、锂片为负极的固态电池,研究其电化学性能。研究发现:当PVDF-HFP和ETPT质量比为1.0∶0.4时,锂离子迁移数达0.89,电化学窗口可达4 V,离子电导率达到8×10^(-5)S/cm,表现出良好的稳定性。将质量比为1.0∶0.4的电解质膜装配成固态电池,经过激活之后,首先在0.1C的倍率下进行测试,首圈充电比容量为133 m A·h/g,首圈放电比容量为129 m A·h/g,在20圈循环测试后,放电比容量也能保持在120 mA·h/g以上,容量保持率为92%。

Solid-state batteries have attracted much attention from researchers because of their excellent performance,but compared with traditional liquid batteries,the weak ion transport capacity is still a major problem,and the reason is that ion transport at solid-solid interface is difficult.A solid electrolyte membrane based on polyvinylidene fluoride-hexafluoropropylene(PVDF-HFP)was prepared,and the effects of PVDF-HFP and plasticizer ethoxylated trimethylolpropane triacrylate(ETPTA)in mass ratios of 1.0∶0.3,1.0∶0.4 and 1.0∶0.5 on ion transport in the electrolyte membrane were investigated,and the electrochemical performance of solid-state batteries with lithium iron phosphate as the positive electrode and lithium sheet as the negative electrode was investigated.It was found that when the ratio of PVDF-HFP to ETPTA was 1.0∶0.4,the lithium ion migration number reached 0.89,the electrochemical window reached 4 V,and the ion conductivity reached 8×10^(-5) S/cm,showing good stability.The electrolyte film with a ratio of 1.0∶0.4 was assembled into a solid-state battery.After activation,the battery was first tested at a rate of 0.1C,the specific charging capacity was 133 mA·h/g and the specific discharge capacity was 129 mA·h/g in the first circle.After the 20-cycle test,the specific discharge capacity could be maintained above 120 mA·h/g,and the capacity retention rate was 92%.