Ionic liquid enabling LAGP/PVDF quasi-solid-state electrolytes with 3D crosslinked networks and reinforced stable interface for lithium metal batteries

Oxide electrolyte Li 1.5 Al 0.5 Ge 1.5 (PO4) 3 (LAGP) has attracted much attention due to their potential and are considered ideal electrolytes for next-generation high-energy-density solid-state lithium metal batteries. However, their application is still limited by problems such as poor solid-solid interface contact, high interface resistance, lithium dendrite growth, and embrittlement during operation. To address these issues, our work propose a synergistic strategy to prepare a novel flexible quasi-solid-state ceramic-polymer electrolyte. This electrolyte is composed of [N1,4,4,4]TFSI ionic liquid (IL), polyvinylidene fluoride (PVDF), LiTFSI salt, and LAGP, which significantly improves the ionic conductivity and cycle stability of the ceramic-polymer electrolyte battery. The prepared LAGP/PVDF composite electrolyte exhibits an ionic conductivity as high as 1.16 × 10 −3  S cm −1 . LAGP nanoparticles have the dual function than not only can reduce the crystallinity of the polymer matrix; but also act as lithium-ion conductors to enhance lithium-ion transport capabilities. Furthermore, the Li/LiFeO 4 battery based on this ceramic-polymer electrolyte exhibits excellent interfacial compatibility and dendrite-free characteristics, with significantly enhanced cycle stability, capable of stable operation exceeding 300 cycles. This work demonstrates the feasibility of the PVDF/LAGP ceramic-polymer electrolyte and its industrial application prospects in solid-state lithium metal batteries.