Quasi-Solid-State Electrolyte Membranes Based on Helical Mesoporous Polysilsesquioxane Nanofibers for High-Performance Lithium Batteries

To solve the safety problem aroused by Li dendrites and liquid electrolytes for lithium batteries, this work reported a new solid-state electrolyte technology. Helical mesoporous 1,4-phenylene bridged and 1,2-ethylidene bridged polysilsesquioxane nanofibers were firstly prepared via a sol-gel transcription method, using self-assembled chiral gelator as the template and organic bridged-siloxane as the precursor. After immersing them in ion liquid electrolyte till absorption saturation, two self-standing ionogel electrolyte membranes (EB-IE and EE-IE) were obtained. Electrochemical test showed that they exhibited good thermal stability (up to 327°C and 293 °C, respectively), wide electrochemical window (4.8 V and 5.6 V, respectively) and ideal room temperature ionic conductivity (up to 0.55 and 2.10 mS cm−1, respectively), which was related to their special organic-inorganic hybrid composition and hierarchical porous nanostructure. When they were applied as electrolyte as well as separator in a LiFePO4/Li cell, they performed excellent cycle stability and superior rate performance, which proved the practicability and feasibility of design and application of nanostructured hybrid polymer as quasi-solid state electrolyte scaffold for safe lithium batteries.