Characterization of Tantalum Oxide Films Prepared by Sol-Gel Process for electrochemical devices

Tantalum oxide films were prepared by sol-gel process using tantalum ethoxide Ta(OC₂H₅)₅. The dependence of deposition conditions (i.e. composition of polymeric solutions and spinning rate) on ionic conductivities for tantalum oxide films were studied. The best results achieved for films fabricated by the spin coating technique were from clear polymeric solutions. These films had low packing density ρ=3.2 g/cm³ and good proton conductivity (about 10^-6 Ω^-1 cm^-1). X-ray photoelectron spectroscopy (XPS) was used for studying the compositions of the tantalum oxide films. We report on the use of tantalum oxide films as ion conductors in devices consisting of WO₃/Ta₂O₅/H⁺ ion storage polymer structure. We found tantalum oxide to have very good properties for proton device applications.