Silica-assisted cross-linked polymer electrolyte membrane with high electrochemical stability for lithium-ion batteries

This study aims to prepare an organic-inorganic reticular polymer electrolyte. Isocyanate acts as a bridge that connects fumed silica and PEO molecular chains. The PEO-TDI-SiO₂ solid polymer electrolytes developed can significantly have improved ionic conductivity of 0.12 mS cm⁻¹ at ambient temperature. This is because the TDI-SiO₂ nanoparticles inhibits polymer crystallization which provides more continuous Li-ion transport pathways. Tests at 60 °C indicate that the cross-linked structure of covalent TSI bonded to PEO effectively enlarges the electrochemical window of the polymer electrolyte to 5.6 V. Also, the PTSI electrolyte membrane has a higher Li⁺ transference number of 0.33 compared to the PEO-LiTFSI electrolytes. It is worth noting that the assembled LiFePO₄|PTSI8%|Li cells deliver outstanding rate performance and stable cycling performance. All these considerable merits of PTSI membrane demonstrate that PTSI is a promising candidate that can be used as solid polymer electrolytes for the next-generation Li-ion batteries.