SrTiO3-modified PVC nano composite proton-conducting electrolytes for primary proton battery applications

In this study, a novel nanocomposite hydrogen(proton) ion-conducting polymer electrolyte(NCPCPE) system was successfully developed. Poly(vinyl chloride) (PVC) served as the polymer matrix, ammonium thiocyanate(NH₄SCN) was used as the ionic salt, and strontium titanate (SrTiO₃) nanoparticles (~ 70.60 nm) acted as the nanofiller. The NCPCPEs were synthesized using the solvent casting method. Among the compositions studied, the system containing 6 wt% SrTiO₃ exhibited the highest ionic conductivity, achieving a value of 1.457 × 10–6 Scm⁻1 at room temperature. Temperature-dependent ionic conductivity analysis confirmed Arrhenius-type behavior. X-ray diffraction(XRD) analysis indicated an increase in the amorphous nature of the polymer matrix upon the incorporation of SrTiO₃. Furthermore, dielectric studies revealed a rise in the dielectric constant with increasing temperature. The total ionic transport number for the most conductive sample was determined to be 0.86, suggesting dominant ion conduction. Additionally, differential scanning calorimetry(DSC) analysis demonstrated a reduction in the glass transition temperature(Tg) upon nanofiller incorporation, indicating that SrTiO₃ functioned as a plasticizing agent within the polymer matrix. A primary proton battery was fabricated and it exhibited an open-circuit voltage of 1.16 V and remained stable for up to 73 h, demonstrating its potential for energy storage applications.