In Situ Exsolved Ni Nanoparticles From Pr _0.5 Sr _0.5 Ti _0.5 Mn _0.5 O ₃ with Varying Ni Doping Levels for Direct Methane Solid Oxide Fuel Cells

ABSTRACT Methane (CH ₄ ), with abundant reserves and mature infrastructure, is an attractive fuel for solid oxide fuel cells (SOFCs). In this work, the effects of Ni doping on the electrochemical performance of Pr _0.5 Sr _0.5 Ti _0.5 Mn _0.5 O ₃ (PSTM)‐based anodes were investigated using Pr _0.5 Sr _0.5 Ti _0.5 Mn _0.4 Ni _0.1 O ₃ (PSTMN41) and Pr _0.5 Sr _0.5 Ti _0.5 Mn _0.5 Ni _0.1 O ₃ (PSTMN51). Ni incorporation and subsequent H ₂ reduction generated highly dispersed Ni nanoparticles and abundant oxygen vacancies, enhancing electron transport and methane conversion. PSTMN41 exhibited superior catalytic activity and stability compared to PSTMN51 in humidified CH ₄ . The PSTMN41‐based cells achieved peak power densities of 119.6 and 60.7 mW·cm ^{− 2} under H ₂ and humidified CH ₄ at 850°C, with polarization resistances of 1.7 and 2.44 Ω·cm ² . Moreover, PSTMN41 maintained excellent stability over 120 h continuous operation in humidified CH ₄ . These results demonstrate that PSTMN41, featuring Ni nanoparticles and high oxygen vacancy concentration, is a promising anode material for SOFCs.