Solid State Electrolytes Prepared from P

All solid state composite electrolytes were prepared using fumed silica (SiO2) silanated with an oligomeric polyethylene oxide silane containing 6-9 ethylene oxide repeat units, a PEO matrix, and LiClO4 (8/10/Li). The PEO-silane covalently attached to the silica was amorphous, with a Tg that increased from -90°C to -53°C after attachment. The conductivity of films prepared using the PEO-silanated silica increased to approximately 6 x 10-5 S/cm at room temperature compared to around 1 x 10-5 S/cm for films prepared with unsilanated silica. The resulting solid state electrolytes (SSEs) can be laminated to the electrodes in lithium metal or lithium-ion rechargeable batteries, ultimately aiming to improve their cycle and shelf-life. The use of polyethylene oxide (PEO) as a SSE at elevated temperatures reveals challenges due to polymer crystallization, which reduces room temperature conductivity. Enhanced room temperature conductivities have been observed in composite polymer electrolytes prepared with inorganic fillers, particularly when utilizing nanoscale silica that prevents crystallization. This study highlights the potential of PEO-silanated silica composites in enhancing ionic conductivity while ensuring mechanical and thermal stability of the solid-state electrolytes.