Optimized electrochemical performance of Pr2NiO4 via partial Ni-substitution with molybdenum

Abstract

This research aimed to develop novel Pr₂NiO₄-based cathodes for solid oxide fuel cells (SOFCs) through partial substitution of Ni with Mo. Pr₂Ni_1-xMo_xO₄ (x = 0, 0.01, 0.015, 0.02, 0.025) cathode powders were prepared via the sol-gel combustion method. The phase structure of the as-prepared powders was characterized by X-ray diffraction (XRD), and the microstructure was examined using scanning electron microscopy (SEM). Electrical conductivity was measured by the DC four-terminal method, and the electrochemical performance of the half-cells was evaluated using electrochemical impedance spectroscopy (EIS). The Pr₂Ni_1-xMo_xO₄ powders exhibiting good chemical stability and thermal expansion matching with the Ce_0.8Gd_0.2O_1.9electrolyte. Mo doping significantly improved the electrical conductivity of Pr₂NiO₄. The electrical conductivity of the Pr₂Ni_0·985Mo_0·015O₄ (x = 0.015) reached 129.07 S cm⁻¹ at 450 °C. EIS results revealed that Mo doping markedly reduced the polarization resistance (Rp), and the lowest value obtained was 0.021 Ω cm² for the Pr₂Ni_0·985Mo_0·015O₄ sample. These findings suggest that Mo-doped Pr₂NiO₄ cathodes possess enhanced oxygen reduction reaction activity.