LATP-PEO复合电解质成膜及离子电导率特性

Film-forming and ionic conductivity characteristics of LATP-PEO composite electrolyte

以纳米Li1.3Al0.3Ti1. 7(PO4)3(LATP)固体电解质为填料,聚氧化乙烯(PEO)为粘结剂,双三氟甲烷磺酰亚胺锂(Li TFSI)为添加剂,乙腈为溶剂,利用流延法制备LATP-PEO固体复合电解质薄膜;采用X射线衍射(XRD)、扫描电镜(SEM)和交流阻抗(EIS)等方法,研究样品的结构特征、形貌特征以及离子导电性能;探讨PEO摩尔质量与含量对LATP-PEO复合电解质薄膜成膜特性的影响。结果表明:PEO摩尔质量为5 000 kg/mol,LATP与PEO质量比为1∶0. 43时,可以获得膜厚为25μm,颗粒分布均匀的柔性LATP-PEO; LATP-PEO离子电导率随温度增高而增大,25℃时为1. 36×10-5S/cm,100℃达到4. 60×10-4S/cm;温度在-20~60℃时,该薄膜离子活化能为4. 86 eV,温度在60~100℃时,离子活化能为0. 22 eV。

Solid composite dielectric films were prepared using a tape casting method with Li1.3Al0.3Ti1.7(P04)3(LATP)particles as filler,polyethylene oxide(PEO)as binder,LiTFSI as additive,and acetonitrile as solvent.X-ray diffraction(XRD),scanning electron microscopy(SEM),and electrochemical impedance spectroscopy(EIS)were used to analyze the structures,morphologies,and ionic conductivities of the samples.The effects of molecular weight and content of PEO on the film forming characteristics of LATP-PEO composite electrolyte films were studied.The results show that a flexible solid composite electrolyte film with a thickness of 25μm can be obtained when the mass ratio of LATP and PEO is 1:0.43.The film processes a uniform particle distribution and high ionic conductivities of 1.36 × 10^-5 S/cm at 25℃ and 4.60 × 10^-4 S/cm at 100 ℃.The ion activation energies are 4.86 eV and 0.22 eV,respectively,when the temperatures are at-20-60 ℃ and 60-100 ℃.