Effect of SIO2 Nano Filler on Structural Properties and Ionic Conductivity of PEO-NACLO4 Polymer System

This thesis investigates sodium-ion solid polymer electrolytes reinforced with nano-alumina, synthesized via solution casting. The research focused on how nanoparticle dispersion influence’s structure, morphology, thermal stability, and electrochemical behavior. Various techniques—XRD, SEM, FTIR, and impedance spectroscopy—were applied. XRD revealed reduced crystallinity of PEO upon SiO₂ incorporation, suggesting a shift toward an amorphous phase favorable for ion transport. FTIR confirmed complexation between PEO chains, sodium ions, and SiO₂, highlighting enhanced salt dissociation. SEM micrographs showed uniform nanoparticle distribution, while impedance spectroscopy indicated that ionic conductivity improved significantly with optimized SiO₂ loading, though excessive filler caused agglomeration and performance decline. The improvements are attributed to increased amorphous content, better ion mobility, and Lewis acid–base interactions at the SiO₂ interface. Overall, the findings demonstrate that SiO₂ nanoparticles effectively tune the microstructure and transport properties of PEO-based electrolytes, underscoring their potential in next-generation solid-state sodium-ion batteries.