Nanostructured Polymer Electrolytes for Li Batteries via the Cross-linking of Self- assembled Lyotropic Liquid Crystals

摘要

A nanostructured polymer electrolyte material for use in Li batteries has been prepared via the polymerization of non-aqueous, lyotropic (i.e., surfactant) liquid crystal (LLC) assemblies. This material is based on a lithium sulfonate surfactant monomer that self- assembles into a type II bicontinuous cubic phase in the presence of propylene carbonate (PC) and its Li-salt solutions. The resulting cross-linked nanocomposite has ordered, 3D-interconnected liquid PC nanochannels and a room-temperature ion conductivity of 10~(-4) to 10~(-3) S cm~(-1) when formed with 15 wt % (0.245 M LiClO4-PC) solution. Liquid-like diffusion in the nanochannels and good ionic conductivity (ca. 10~(-4) S cm~(-1) ) are retained down to –65 °C. Li-metal batteries with voltages in the 3.5 V range have been successfully made using this material. Studies varying the amount and type of liquid electrolyte, free Li salt, etc. indicate that higher conductivities and better battery performance should be possible.