Dual‐Alloy Exsolution in Fe‐Based Perovskite Anodes for High‐Performance Direct Ammonia Solid Oxide Fuel Cells

ABSTRACT

Direct ammonia solid oxide fuel cells (DA‐SOFCs) offer an integrated route for carbon‐free power generation by coupling in situ ammonia decomposition with electrochemical hydrogen oxidation. However, anode catalysts must simultaneously achieve rapid NH ₃ decomposition, efficient electrochemical charge transfer, and long‐term resistance to nitridation and particle coarsening. Here, we report an Fe‐based perovskite multi‐doped with Co and Ni, La _0.6 Sr _0.2 Ba _0.2 Mn _0.2 Fe _0.6 Co _0.1 Ni _0.1 O ₃ (P‐LSBMFCN), as a precursor for dual‐alloy exsolved DA‐SOFC anodes. Upon H ₂ reduction, P‐LSBMFCN transforms into a Ruddlesden‐Popper (RP) layered oxide decorated with highly dispersed FeCo and FeNi alloy nanoparticles (R‐LSBMFCN). Co and Ni multi‐doping directs the reduction‐induced nucleation and alloying pathway, reducing the average nanoparticle size from 129.3 nm for the Fe‐only reference to 48.3 nm for R‐LSBMFCN while increasing nanoparticle density. The resulting dual‐alloy architecture provides abundant accessible active sites and electronically tuned metal surfaces, accelerating NH ₃ activation, NH _x intermediate conversion, and N recombination/desorption. Consequently, R‐LSBMFCN exhibits the lowest apparent activation energy, nearly complete NH ₃ conversion at high temperature, and maximum power densities of 1.638 and 1.386 W cm ⁻² under H ₂ and NH ₃ at 800°C, respectively, with stable operation for 200 h under NH ₃ . This work demonstrates multi‐doping‐induced dual‐alloy exsolution as an effective strategy for durable DA‐SOFC anodes.