Enhanced oxygen electrode performance in solid oxide fuel cells via La-doping of Pr2NiO4+δ-based Ruddlesden–Popper perovskites†

Abstract

Solid oxide fuel cell (SOFC) is a high-efficiency, low-carbon power generation device that directly converts the chemical energy of fuel directly into electricity at elevated temperatures. However, the performance of the oxygen electrode, which is critical for the oxygen reduction reaction (ORR), remains limited by high polarization losses and limited long-term stability. Ruddlesden–Popper (R–P) perovskites, such as Ln₂NiO_4+δ (Ln = La, Pr, Nd), offer excellent oxygen transport due to their unique A–O rock salt layers. In this study, La³⁺-doped Pr_2−xLa_xNi_0.8Cu_0.2O_4+δ (x = 0, 0.5, 1.0, PL_xNC) oxygen electrode materials are synthesized by the sol–gel method, and their electrochemical properties are systematically investigated. While the electrical conductivity decreases with increasing La³⁺ content, PL_0.5NC exhibits optimal oxygen surface exchange and bulk diffusion properties. SOFC using PL_0.5NC as the oxygen electrode achieved excellent performance at 800 °C, with a polarization resistance of 0.245 Ω cm² and a peak power density of 0.864 W cm⁻², a 64% improvement over PNC. This study highlights the potential of La³⁺ doping to enhance PNO-based oxygen electrodes and provides insight into the development of high performance SOFC materials.