Porous Composite Gel Polymer Electrolyte with Interfacial Transport Pathways for Flexible Quasi Solid Lithium-Ion Batteries
Yanjun Xu, Lina Gao, Xianzhang Wu, Shengzhao Zhang, Xiuli Wang, Changdong Gu, Xinhui Xia, Xueqian Kong, Jiangping Tu
Abstract
The growing demand for safer energy storage devices leads to wide research on solid-state lithium-ion batteries. However, as an important component in the solid-state battery, the solid-state electrolyte often encounters problems, especially the low conductivity at room temperature, inhibiting the development of solid-state batteries. Here, improved electrochemical performances of lithium-ion batteries are obtained by designing a composite gel polymer electrolyte with a sponge-like structure. The porous composite gel polymer electrolyte (PCGPE) is developed by a facile phase inversion process of poly(vinylidiene fluoride-hexafluoropropylene) (PVdF-HFP) and Li6.4La3Zr1.4Ta0.6O12 (LLZTO). The solid-state nuclear magnetic resonance test proves the continuous porous structure constructs fast Li-ion transport pathways on internal interfaces. As a result, the ionic conductivity of PCGPE is up to 5.45 × 10–4 S cm–1 at room temperature. Moreover, an initial capacity of 142.2 mAh g–1 and 82.6% capacity retention at 1 C after 350 cycles are successfully achieved in flexible LiFPO4//PCGPE//Li batteries.