Nanocomposite network polymer gel-electrolytes: TiO₂- and Li₂TiO₃-nanoparticle effects on their structure and properties

Abstract

The effects of TiO₂-(∼60 nm) and Li₂TiO₃-(∼20 nm) nanoparticles on the conductivity, structure, and mechanical strength of (polyether diacrylate-LiClO₄-ethylene carbonate)-based polymer gelelectrolytes are studied. When the gel-electrolytes are synthesized with the TiO₂- and Li₂TiO₃-nanoparticles ultrasonic pretreatment, both polyether diacrylate and ethylene carbonate are partially decomposed in the solution; this is evidenced by the appearance of -CH₃-group signal at 1.2 ppm in ¹H-NMR-spectra, as well, as by the peak area analysis. The gel-electrolyte matrix partial decomposition was shown not to affect the network polymer electrolyte conductivity and mechanical properties. Analysis of NMR spectra for ⁷Li nuclei, taken with nanocomposite polymer electrolyte rotating under magic angle, revealed two Li⁺ ion environments: with the nanoparticles and the polymer matrix. Upon the adding of TiO₂ nanoparticles (10 mass %) the polymer electrolyte conductivity increased by order of magnitude (up to 1.8 × 10⁻³ S/cm at 20°C); upon the adding of Li₂TiO₃, by a factor of 2 only (up to 7.0 × 10⁻⁴ S/cm at 20°C). The electrolyte-solution ultrasonic treatment increased the films’ mechanical strength; the larger effect occurred with Li₂TiO₃ (the modulus of elasticity is 15 MPa).