Mechanical and Electrochemical Properties of New Nanocomposite Polymer Electrolytes Based on Poly(vinylidene fluoride-co-hexafluoropropylene) and SiO2 Addition

Nanocomposite polymer electrolytes based on the system poly(vinylidene fluoride-co-hexafluoropropylene)–liquid electrolyte 1 mol/L LiBF 4 in gamma-butyrolactone which is modified by introducing up to 10 wt % of SiO 2 nanopowder (an average particle size of 7 nm) are synthesized and characterized. The introduction of SiO 2 nanoparticles worsens the elasticity of films but increases their fracture stress to 24 MPa. The conductivity of the nanocomposite electrolytes containing SiO 2 nanoparticles is higher than that without SiO 2 and attains 3.7 mS/cm at 20°C for the electrolyte containing 1.25 wt % SiO 2 . Upon the introduction of SiO 2 nanoparticles, the electrochemical stability of electrolytes grows by 0.50–0.85 V and attains 6.7 V relative to Li/Li + .