Synergized Tri‐Phase Anode via Purposive Ba ²⁺ Doping at the La ³⁺ Site in LaFe _0.7 Ni _0.3 O _3‐δ for Improved SOFC Performance

ABSTRACT 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 Ba ²⁺ at the La ³⁺ site of La _0.5 Ba _0.5 Fe _0.7 Ni _0.3 O _3‐δ under reducing atmosphere triggers the formation of Ruddlesden‐Popper perovskite (La ₂ Ba)Fe ₂ O ₇ , hexagonal Ba ₆ La ₂ Fe ₄ O ₁₅ , and exsolved cubic Ni ₃ Fe 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 cm ² ), doubled PPD with a record value of 1.25 W cm ⁻² at 800 °C of that without Ba ²⁺ doping, negligible voltage decrease rate of ∼8.9 × 10 ⁻⁵ ·V h ⁻¹ , and 300‐h durability operated at 750°C.