摘要
Composite solid electrolytes (CSEs), which combine garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), are a promising material for safe and high-performance solid-state lithium batteries (SSLBs). However, a significant challenge in this CSE fabrication is the spontaneous gelation that occurs between PVDF-HFP and LLZTO during the initial slurry preparation. This gelled electrolyte slurry severely hinders subsequent processability and film casting, resulting in thick, non-uniform membranes that ultimately reduce ionic conductivity. In this study, we identify the moisture-sensitive surface of LLZTO as the primary trigger for PVDF-HFP gelation in the electrolyte slurry. Interestingly, a simple pre-drying treatment of LLZTO is found to be highly effective in completely preventing this gelation. This breakthrough enables uniform dispersion and the formation of thin, flexible, high-powder-loading membranes. Compared to CSEs made from gelled slurry, the CSE produced from de-gelled slurry demonstrates favorable ionic conductivity (> 10(-4) S cm(-1) at 25 degrees C), a wider electrochemical stability window (up to 4.9 V), and improved interfacial compatibility with lithium metal, thereby facilitating stable lithium plating and stripping and significantly enhancing the overall performance of SSLBs.