Proton Conducting Fuel Cells Using the Indium-doped Cerium Diphosphate Electrolyte

Abstract

Proton conductivity of indium-doped cerium diphosphate (CeP₂O₇) was investigated to explore its potential for application as an electrolyte in intermediate temperature fuel cells. The In³⁺-doped CeP₂O₇ powder was synthesized by the digestion of metal oxide in a phosphoric acid solution. The structure and ion conductivity of In³⁺ doped CeP₂O₇ were analyzed using X-ray diffraction, scanning electron microscopy (SEM), infrared spectroscopy, and electrochemical impedance spectroscopy (EIS). Under humidified conditions, the In³⁺- doped CeP₂O₇ exhibited sufficient conductivity in the intermediate temperature range. The maximum ionic conductivity of Ce_0.95In_0.05P₂O₇ was 2.31x10^-2 Scm^-1 at 180 °C. The maximum power density of the H₂/air fuel cells fabricated using the Ce_0.95In_0.05P₂O₇ electrolyte (0.40 mm thickness) was 54.4 mWcm^-2 generated at 220 ^oC. The results indicate that Ce_0.95In_0.05P₂O₇ is a promising material for the fabrication of intermediate temperature fuel cells.