PEO基复合固态电解质的制备及性能研究

Preparation and Properties of PEO-based Composite Solid Electrolyte

高安全性的固态锂离子电池是目前研究的热点之一,固态电解质是实现固态全电池的关键。本文采用两段式高温烧结法制备NASICON结构的Li1.5Al0.5Ge1.5(PO4)3(LAGP)固态电解质填料,采用溶胶-凝胶浇注法制备PEO基复合固态电解质膜,通过XRD、SEM测试其物相和形貌特征,通过线性扫描伏安法、电导率测定、循环伏安法等测试其电化学性能。结果表明,制备的LAGP峰型明显,基本无杂峰出现,说明样品纯度较高。微观形貌(SEM)中可见LAGP粉末镶嵌在PEO膜中形成复合固态电解质膜,表明用溶胶-凝胶浇注法制备的PEO基固态电解质膜既具有有机聚合物PEO柔软、贴合性好的特性,同时也有无机陶瓷粉末LAGP较高电导率的性能。当LAGP占有机物PEO和LAGP总量的60%时,电导率最高,达到2.16×10^-4 S·cm^-1,PEO基固态电解质膜具有0.5~8 V的电化学窗口。

Solid-state lithium-ion batteries with high security are one of the hotspots of current research. Solid-state electrolyte is the key to realize solid-state battery.In this paper, NASICON structure Li1.5Al0.5Ge1.5(PO4)3(LAGP) solid electrolyte filler was prepared by two stage high temperature sintering method, and PEO based composite solid electrolyte membrane was prepared by sol-gel casting.The phase and morphology were measured by XRD,SEM, and the electrochemical properties were measured by linear sweep Voltammetric method, conductivity measurement and cyclic Voltammetric method.The results showed that the prepared LAGP had obvious peak shape, high strength and no impurity peaks, which indicated that the sample had high purity.Microscopic morphology (SEM) showed that LAGP powder was embedded in PEO film to form composite solid electrolyte film.The PEO based solid electrolyte film prepared by sol-gel pouring method not only has the softness and good fit of organic polymer PEO, but also has the high conductivity of inorganic ceramic powder LAGP.When LAGP occupies 60% of the total amount of PEO and LAGP, the conductivity is the highest, reaching 2.16 × 10^-4 S.cm^-1.PEO-based solid electrolyte membranes have an electrochemical window of 0.5~8 V.