A gel polymer electrolyte based on IL@NH2-MIL-53 (Al) for high-performance all-solid-state lithium metal batteries

Solid polymer composite electrolytes possess the benefits of superior compatibility with electrodes and good thermal characteristics for more secure energy storage equipment. Herein, a new gel polymer electrolyte (GPE) containing NH2-MIL-53(Al), [PP13][TFSI], LiTFSI, and PVDF-HFP was prepared using a simple method of solution casting. The effects of encapsulating different ratios of ionic liquid ([PP13][TFSI]) into the micropores of functionalized metal-organic frameworks (NH2-MIL-53(Al)) on the electrochemical properties were compared. XRD, SEM, nitrogen adsorption-desorption isotherms, and electrochemical measurements were conducted. This GPE demonstrates a superior ionic conductivity of 8.08 × 10−4 S·cm−1 at 60 °C and can sustain a discharge specific capacity of 156.6 mA·h·g−1 at 0.2 C for over 100 cycles. This work might offer a potential approach to alleviate the solid-solid contact with the solid-state electrolyte and electrodes and broaden a new window for the creation of all-solid-state batteries.