Modifying Mn-based R-P phase cathode properties for proton-conducting solid oxide fuel cells

Tailoring B-site metal in K2NiF4-type R-P (Ruddlesden-Popper) oxide could affect crystal structure, electronic states, oxygen and chemical environment, thus potentially altering surface properties and leading to enhanced electrocatalysis. Hence, in this study, a Mn-based R-P phase LSMO (La0.5Sr1.5MnO4+δ) is firstly modified via B-site Fe-doping, impelling proton/oxygen ion diffusion and surface exchange evidently. The electrical conductivity relaxation (ECR) results give further evidence. When assessed the Fe-modified single-phase cathode La0.5Sr1.5Mn0.8Fe0.2O4+δ based on a proton-conducting solid oxide fuel cell (H-SOFC), a preeminent power output of 1250 and 644 mW cm-2, corresponding to polarization resistances of 0.070 and 0.367 Ω cm2 at 700 and 600 °C, is acquired. This cell performance outperforms Fe-free LSMO and Ln2NiO4-based single-phase cathodes reported in the literature. Due to the superior cell electrochemical performance accompanied by a fine operational stability, Fe-modified LSMO is a great potential alternative for low-temperature high-performance H-SOFCs.