A multi-affinity supramolecular nanolayer reinforced PVDF-LLZTO composite polymer electrolyte for stable solid-state lithium batteries

Technical breakthrough of composite polymer electrolyte (CPE) is one of the key factors that determines the commercial process of the current solid-state lithium battery. performances. It is crucial to optimize the design of multiphase interfaces among different components in CPE for regulating Li+ (12C4-TFSI) supramolecular nanolayer is introduced into poly(vinylidene difluoride)-Li6.75La3Zr1.75Ta0.25O12 (PVDF-LLZTO) CPE as interface modifier. As a result, enhanced Li+ conductivity of 4.29 x 10-4 S center dot cm-1, Li+ transfer number of 0.44, and stable electrochemical window voltage of 4.8 V vs. Li/Li+ at 30 degrees C are obtained. The symmetric Li||Li cell exhibits an improved critical current density (CCD) of 1.2 mA center dot cm-2 and steady cycling at 0.2 mA center dot cm-2 for over 850 h without visible voltage fluctuation. The assembled Li||LiFePO4 coin solid-state cell delivers a high initial discharge capacity of 172.9 mAh center dot g-1 at 0.1 C, rate capability (up to 5.0 C) and outstanding cycling stability with a capacity retention of 87.2% after over 750 cycles at 1.0 C. The associated Li||LiFePO4 pouch cell presents an initial specific discharge capacity of 112.3 mAh center dot g-1 and successfully runs 30 cycles with a final capacity of 101.8 mAh center dot g-1. This work offers a facile strategy to optimize multiphase interfaces of PVDF-LLZTO CPE for stable solid-state lithium battery.