Illite-reinforced polymer/inorganic hybrid electrolytes for high-performance solid-state Lithium-metal batteries

A composite polymer electrolyte (CPE) was developed by incorporating illite inorganic fillers into a polyethylene oxide (PEO) matrix with a UV-activated crosslinking agent. The illite fillers suppressed PEO crystallinity, enhanced Li-ion transport, and reinforced mechanical stability. The optimized CPE showed an ionic conductivity of 8.59 × 10 −5 S cm −1 at room temperature (25 °C) and a tensile strength of 9.86 MPa, and a LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NCM622)//Li coin cell incorporating the optimized CPE delivered a discharge capacity of 128 mAh g −1 after 100 cycles. This strategy offers a promising route to safe, high-performance solid-state lithium-metal batteries. • Composite polymer electrolytes were obtained with illite fillers and UV crosslinking. • Ilite filler improved Li-ion conductivity and mechanical properties of the electrolyte. • Illite filler suppresses polymer chain crystallinity and improves interfacial stability. • Long-term electrochemical stability was achieved using illite and UV crosslinking.