Akademik Veri Yönetim Sistemi
Composites Communications, cilt.57, 2025 (SCI-Expanded)
The impacts of titanium dioxide (TiO2) filler on the dielectric response of ionic liquid (IL)-doped sulfonated polyether ether ketone (SPEEK) electrolytes have been investigated. Neat SPEEK, IL-doped SPEEK (SPIL), and IL-doped TiO2-filled SPEEK (SPILTO) composite membranes were prepared with the conventional solution cast method and characterized by various techniques. Fourier-transform infrared (FTIR) spectroscopy analyses confirmed the sulfonation and also showed the dispersion of imidazole and TiO2. Thermogravimetric analysis (TGA) results showed that all composites are thermally stable to comply with electrochemical requirements up to nearly 150 °C. SPILTO-1 composite exhibited a storage modulus of 74 MPa and a glass transition temperature (Tg) of 140 °C. More than 1 wt% TiO2 fillers resulted in heterogeneous membrane surfaces for SPILTO samples. The SPILTO-1 electrolyte showed a maximum conductivity (σ) of 8.1 × 10−4 S/cm and a significant proton transport potential even in completely anhydrous conditions. Charge carrier migration and accumulations resulted in high dielectric constant (ε′) values and major polarization, particularly at lower frequencies. The dielectric permittivity of the SPEEK matrix increased dramatically with the addition of IL and TiO2 fillers. The substantial ε′ values of SPILTO-1 showed that the combination of IL and TiO2 increases both the number of free mobile ions and the charge stored in the electrolytes. In the relaxation behaviors, the shortest relaxation time (τ) of 1.34 μs at 300 K corresponded to the highest conductivity of SPILTO-1 electrolyte.