In situ establishment of rapid lithium transport pathways at the electrolytes-electrodes interface enabling dendrite-free and long-lifespan solid-state lithium batteries

Abstract

Composite solid-state electrolytes (CSEs) exhibit the high ionic conductivity of ceramic electrolytes and the facile processing and good flexibility of polymer electrolytes, representing the most promising class of solid-state electrolytes for the industrialization of lithium batteries. Nevertheless, CSEs continue encountering substantial interfacial resistance, which impedes their practical deployment. In response to these issues, a Li_6.4La₃Zr_1.4Ta_0.6O₁₂/poly(vinylidene fluoride) (LLZTO/PVDF) solid electrolyte membranes with a thickness of 25 μm were prepared by the doctor blade method. In situ polymerization of 1,3-dioxolane (DOL) at the electrolyte–electrode interface was initiated by lithium hexafluorophosphate (LiPF₆) and lithium difluoro(oxalate)borate (LiDFOB) dual-salts to produce poly(1,3-dioxolane) (PDOL). The presence of PDOL in LLZTO/PVDF@PDOL results in a high room temperature ionic conductivity of 3.578 mS cm⁻¹. Moreover, the Li||LLZTO/PVDF@PDOL||LiFePO₄(LFP) battery exhibits a discharge-specific capacity of 143 mAh g⁻¹ and capacity retention of 81.7 % after 1000 cycles at 2 C, and the pouch cell with LLZTO/PVDF@PDOL achieved a high energy density of 190 Wh kg⁻¹. The findings of this study may facilitate the industrial application of CSEs.