Confinement of Ionic Liquid in Zeolite Nanochannels Synergistically Enhances Ion Transport and Interface Stability in PVDF-HFP-Based Composite Solid-State Electrolytes

Polymer-based solid-state electrolytes provide significant advantages in flexibility, lightweight characteristics, and scalability, rendering them highly promising for high-performance solid-state lithium metal batteries with improved safety. Nonetheless, obstacles, such as inadequate structural uniformity, slow Li+ transport kinetics, and insufficient interfacial compatibility, impede their practical utilization. This research employs the distinctive porous architecture of zeolite to restrict the mobility of ionic liquid [EMIM][TFSI], resulting in the synthesis of an innovative filler IL@Zeolite, which is integrated with PVDF-HFP to create composite polymer electrolytes. The filler decreases polymer crystallinity, aids in the dissociation of lithium salts, and creates new pathways for Li+ transport, thereby significantly enhancing the Li+ transfer kinetics. A conductivity of 0.89 mS cm–1 and Li+ transference number of 0.67 are attained. Simultaneously, it generates an SEI layer with a high LiF content, efficiently bridging the interface between the electrolyte and electrode. As a result, the fabricated lithium symmetric battery can consistently cycle for over 7000 h at a current density of 0.1 mA cm–2, whereas the solid-state LFP battery exhibits a capacity retention of 96.5% after 370 cycles at 0.2C (1C = 170 mAh g–1) and 86% after 500 cycles at 1C. The constructed solid-state lithium–oxygen battery can reliably cycle beyond 400 cycles. This offers a novel approach to enhance the efficacy of polymer solid-state electrolytes.