Synergized Tri-Phase Anode via Purposive Ba²⁺ Doping at the La³⁺ Site in LaFe_0.7Ni_0.3O_3-δ for Improved SOFC...

Although perovskites are promising anode materials for solid oxide fuel cells (SOFCs), poor hydrogen oxidation reaction (HOR) kinetics and low peak power density (PPD) are usually limited by the single-phase composition. Herein, purposive doping of Ba²⁺ at the La³⁺ site of La_0.5Ba_0.5Fe_0.7Ni_0.3O_3-δ under reducing atmosphere triggers the formation of Ruddlesden-Popper perovskite (La₂Ba)Fe₂O₇, hexagonal Ba₆La₂Fe₄O₁₅, and exsolved cubic Ni₃Fe nanoparticles, which facilitates excellent ionic and electronic conductivity, extra oxygen vacancies, and accelerated HOR kinetics. The as-fabricated SOFC containing a tri-phase anode made from the above composite leads to 57% polarization resistance reduction (from 0.28 to 0.12 Ω cm²), doubled PPD with a record value of 1.25 W cm^-2 at 800 °C of that without Ba²⁺ doping, negligible voltage decrease rate of ∼8.9 × 10^-5·V h^-1, and 300-h durability operated at 750°C.