Enhancing the properties of PEG-based solid polymer electrolytes with TiO2 nanoparticles for potassium ion batteries

Abstract

In this study, nanocomposite solid polymer electrolytes (NSPEs) based on poly(ethylene glycol) (PEG), potassium nitrate (KNO3), and titanium oxide (TiO2) nanoparticles were synthesized using a solution casting technique. The impact of various TiO2 nanoparticle concentrations on the structural, thermal, electrical and electrochemical properties of the NSPEs was investigated. X-ray diffraction analysis revealed a decrease in the degree of crystallinity of the PEG–KNO3 electrolyte upon the addition of TiO2 nanoparticles. Differential scanning calorimetry measurements showed a decrease in the melting temperature of the NSPE with the incorporation of 6 wt.% TiO2 nanoparticle concentration. The ionic conductivity of the NSPEs increased with TiO2 concentration up to 6 wt.% (σ = 5.94 × 10−5 S/cm), beyond which a decrease was observed. Transference number measurements confirmed the dominance of ionic charge transport in the NSPE. A solid-state electrochemical cell fabricated using the optimal NSPE composition (80PEG–20KNO3–6 wt.% TiO2) exhibited promising discharge performance under a constant load of 100 kΩ.

Keywords

• Nanocomposite polymer electrolyte
• PEG
• TiO2 nanoparticles
• Ionic conductivity
• Electrochemical performance