Nano-fumed SiO2 modified polyethylene oxide-based inorganic/polymer composite solid electrolyte for room temperature

Solid polymer electrolytes (SPEs) are flexible and exhibit wide application prospects. However, their low ionic conductivity at room temperature largely restricts their practical use in next-generation solid-state lithium batteries. A composite polymer electrolyte (CPE) that combines the advantages of soft chains and rigid particles is constructed to balance the electrochemical properties and mechanical strength. Hydrophobic nano-fumed silica (SiO 2 ) fillers are uniformly distributed in the dense cross-linking -CH 2 -CH 2 O- network, which is composed of polyethylene oxide and tetraglyme that is triggered by ultraviolet irradiation. The increasing amorphous region of the resulting CPE, due to the cross-linking and nanoparticles doping, facilitates an excellent electrochemical property with an ionic conductivity of 0.29 mS·cm − 1 and a lithium transference number of 0.60 at room temperature. Moreover, the compact film with a tensile elongation of 57% can provide close interfacial contact and ensure more security for cells at work. The assembled Li||LiFePO 4 cells can deliver a reversible specific capacity of 160 mAh g − 1 at 0.1 C at room temperature and a capacity retention of 98% after 100 cycles. This study proposes a novel method for creating high-performance composite solid electrolytes at room temperature.