Proton-conducting zirconium phosphate glass thin films

► P2O5 powder was added to 30 mL of 2-methoxyethanol. ► This solution was stirred at room temperature until a transparent solution was obtained. ► Zirconium tetra-n-butoxide was also added to 30 mL of 2-methoxyethanol, and the two solutions were mixed with P/Zr molar ratios of 0.2 and 4.6. ► The zirconium phosphate glass thin films with various phosphorus contents were fabricated by the spin-on-glass technique. ► The conductivity of the high-phosphorus-concentration glass thin film was 3.16 × 10-5 S/cm at temperatures of up to 350 °C even in the absence of humidity.