Fabrication and Fuel Cells Performance of Lanthanum-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 La³⁺-doped CeP₂O₇ powder was synthesized by the digestion of metal oxide in a phosphoric acid solution. The structure and ion conductivity of La³⁺ doped CeP₂O₇ were analysed using X-ray diffraction, scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Under humidified conditions, the La³⁺-doped CeP₂O₇ exhibited sufficient conductivity in the intermediate temperature range. The maximum ionic conductivity of Ce_0.95La_0.05P₂O₇ was 2.00 × 10^-2 Scm^-1 at 180 °C. The maximum power density of the fabricated H₂/air fuel cells using the Ce_0.95La_0.05P₂O₇ as electrolyte (0.44 mm thickness) was 49.0 mW cm^-2 at 240 °C. The results indicate that Ce_0.95In_0.05P₂O₇ is a promising material for the fabrication of intermediate temperature fuel cells.