Synergistic Influence of ZnO Nanofillers and Sodium Alginate on Ionic Transport in PVA/NaCMC Polymer Electrolytes for Primary Battery Systems

Solid polymer electrolytes (SPEs) composed of sodium carboxymethyl cellulose (NaCMC), sodium alginate (SA) and poly (vinyl alcohol) (PVA) integrated with zinc oxide (ZnO) nanoparticles were prepared via solution casting. FTIR and XRD analyses confirmed the interactions between the components and the presence of crystalline ZnO with a Wurtzite structure, while SEM and EDX revealed uniform dispersion of nanoparticles. Thermal analyses (DSC, TGA) indicated the enhanced thermal stability. The highest conductivity of 8.23 × 10 ^− 6 S cm⁻¹ is observed for the sample with 2 wt.% ZnO for room temperature, which also showed increasing conductivity with temperature. Dielectric studies revealed space charge polarization effects and temperature-dependent relaxation behaviour. The ionic transference number was 0.74, indicating dominant ionic conduction. The best-performing sample, when employed in a primary battery, delivered a zero-load voltage of 1.373 V, area density of current 1946.9 µA cm⁻², specific energy of 21.57 Wh kg⁻¹, power flux density of 1.035 W kg⁻¹, and nominal capacity of 458.3 mAh g⁻¹, demonstrating its potential for energy storage applications.