Fabrication of PEO-PMMA-LiClO4-Based Solid Polymer Electrolytes Containing Silica Aerogel Particles for All-Solid-State Lithium Batteries

Abstract

To improve the ionic conductivity and thermal stability of a polyethylene oxide (PEO)-ethylene carbonate (EC)-LiClO4-based solid polymer electrolyte for lithium-ion batteries, polymethyl methacrylate (PMMA) and silica aerogel were incorporated into the PEO matrix. The effects of the PEO:PMMA molar ratio and the amount of silica aerogel on the structure of the PEO-PMMA-LiClO4 solid polymer electrolyte were studied by X-ray diffraction, Fourier-transform infrared spectroscopy and alternating current (AC) impedance measurements. The solid polymer electrolyte with PEO:PMMA = 8:1 and 8 wt% silica aerogel exhibited the highest lithium-ion conductivity (1.35 × 10−4 S∙cm−1 at 30 °C) and good mechanical stability. The enhanced amorphous character and high degree of dissociation of the LiClO4 salt were responsible for the high lithium-ion conductivity observed. Silica aerogels with a high specific surface area and mesoporosity could thus play an important role in the development of solid polymer electrolytes with improved structure and stability.