Bikitaite composite polymer electrolyte for high-performance solid-state lithium metal battery

Abstract

Ceramic-polymer hybrids promise to form composite electrolytes with high ionic conductivity, good stability, and electrode compatibility that conventional ceramic or polymer electrolytes cannot achieve. Using ceramic fillers in polymer electrolytes frequently results in significantly improved ion conduction. This study employs a representative composite electrolyte based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), Li zeolite Li2(Al2Si4O12) (bikitaite, BKT) ceramics, and an ether-based dual salt containing Li nitrate (EDSN) electrolyte as a plasticizer. The resulting composite electrolyte composed of PVdF, EDSN, and BKT has a superior ionic conductivity of 1.03 × 10–3 S cm−1, a broader electrochemical window of 4.8 V, and a high Li transference number of 0.61. The assembled solid-state LiFePO4/Li metal battery demonstrates a long lifespan, with an outstanding capacity retention of 86% after 450 cycles at 0.3C. The developed electrolyte with long cycling stability may serve as a model for developing solid electrolytes for Li metal secondary battery applications.