ABSTRACT

All-solid-state Li-ion batteries, have become increasingly important because of their highly reliable solid electrolyte materials. Flexible solid polyethylene oxide (PEO) based electrolytes have been widely studied. Nevertheless, this material exhibits low lithium-ion conductivity. Herein, we report the optimisation of the composition of PEO/polyvinylidene fluoride (PVDF)-based electrolytes to enhance ionic conductivity. When the weight ratio of lithium bis(trifluoromethane sulphonyl)imide and PEO/PVDF is 1:5 (LiTFSI:PEO/PVDF = 1:5), maximum conductivities are 2.98 × 10⁻⁵ S cm⁻¹ at 30°C and 5.56 × 10⁻⁴ S cm⁻¹ at 60°C. Furthermore, the all-solid-state battery using this solid electrolyte film, a Li metal anode, and a LiFePO₄ cathode delivers initial discharge capacities of 149.6 mAhg⁻¹ (0.1 C, 60°C) and 130.2 mAh g⁻¹ (0.5 C, 60°C). Meanwhile, the solid-state lithium battery also presents good cycling performance and excellent rate capability at 60°C.

摘要

全固态锂离子电池因其高度可靠的固体电解质材料而变得越来越重要。基于柔性固体聚环氧乙烷（PEO）的电解质已被广泛研究。然而，这种材料表现出低的锂离子电导率。在此，我们报告了优化 PEO/聚偏二氟乙烯 (PVDF) 基电解质的组成以提高离子电导率。当双(三氟甲磺酰)亚胺锂与PEO/PVDF的重量比为1:5 (LiTFSI:PEO/PVDF = 1:5)时，最大电导率为2.98 × 10 ^-5 S cm ^-1 at 30°C和5.56 × 10 ^-4 S cm ^-1在60°C。此外，使用这种固体电解质膜、锂金属负极和 LiFePO 的全固态电池₄阴极提供 149.6 mAhg ^-1 (0.1 C, 60°C) 和 130.2 mAh g ^-1 (0.5 C, 60°C) 的初始放电容量。同时，固态锂电池在60℃下也表现出良好的循环性能和优异的倍率性能。