Ion-conductive and mechanical properties of polyether/silica thin fiber composite electrolytes

To enhance the ionic conductivity and mechanical strength of existing polymer electrolytes, we have composited a submicro-scaled non-calcined silica thin fiber (ncl-SiF) in a polyether electrolyte. Composite electrolytes were prepared using polyether and inorganic fillers, including 5 mol% of lithium bis-(trifluoromethane sulfonyl) imide (LiTFSI), and the ionic conductivity and mechanical strength were measured. The submicro-scaled ncl-SiF composite improved the conductivity of the electrolyte, with the highest conductivity exceeding 10−4 S/cm at 30 °C. The stress-strain curves showed significant increases in the Young's modulus and the stress at break for the composite samples, and the highest value of the Young's modulus exceeded that of the original 10-fold. Thus, we conclude that highly dispersive ncl-SiF is a highly suitable material for the improvement of ionic conductivity and mechanical strength.