A gel polymer electrolyte with IL@UiO-66-NH2 as fillers for high-performance all-solid-state lithium metal batteries

All solid-state electrolytes have the advantages of good mechanical and thermal properties for safer energy storage, but their energy density has been limited by low ionic conductivity and large interfacial resistance caused by the poor Li⁺ transport kinetics due to the solid–solid contacts between the electrodes and the solid-state electrolytes. Herein, a novel gel polymer electrolyte (UPP-5) composed of ionic liquid incorporated metal-organic frameworks nanoparticles (IL@MOFs) is designed, it exhibits satisfying electrochemical performances, consisting of an excellent electrochemical stability window (5.5 V) and an improved Li⁺ transference number of 0.52. Moreover, the Li/UPP-5/LiFePO₄ full cells present an ultra-stable cycling performance at 0.2C for over 100 cycles almost without any decay in capacities. This study might provide new insight to create an effective Li⁺ conductive network for the development of all-solid-state lithium-ion batteries.