Highly porous star-crosslinked POSS-based single-ion conducting hybrid electrolytes enabling fast ion transport for dendrite-free lithium metal batteries

High-performance lithium metal batteries demand polymer electrolytes materials possessing excellent electrochemical performance, mechanical properties and interfacial compatibility. However, the low ionic conductivity, significant polarization and parasitic side reactions observed in conventional polymer electrolytes hinder their practical application. In this work, novel POSS-based single-ion conducting hybrid electrolytes (PSCHEs) with a star -crosslinked network were synthesized by introducing multifunctional POSS into single-ion conducting polymer chains through epoxy ring-opening polymerization. These PSCHEs exhibit a high porosity exceeding 90 %, a room-temperature ionic conductivity of 1.15 × 10 −4  S cm −1 , a high lithium-ion transference number of 0.80 and a wide electrochemical window of 4.8 V. Furthermore, the formation of a stable LiF and Li x SiO y -rich SEI layer at the lithium metal anode interface and excellent interfacial compatibility between the electrolytes and the electrodes were demonstrated, enabling stable lithium plating/stripping for over 1400 h at a current density of 0.1 mA cm −2 . The Li|PSCHEs|LiFePO 4 cells exhibit good cycling and rate performance at room temperature. This work offers a promising strategy for designing polymer electrolytes with a range of desirable properties for high-performance lithium metal batteries.