Efficient and Robust Nanocomposite Cermet Anode with Strong Metal–Oxide Interaction for Direct Ammonia Solid Oxide Fuel Cells

Abstract Direct ammonia solid oxide fuel cells (DA‐SOFCs) offer a promising pathway for the efficient utilization of carbon‐free ammonia fuel. However, the nitridation of nickel‐based cermet anodes in ammonia causes rapid microstructural coarsening, leading to durability problems. Herein, an efficient, ammonia‐tolerant Fe‐modified Ni‐Gd _0.1 Ce _0.9 O _1.95 (NiFe‐GDC) nanocomposite anode is developed by coupling a self‐assembly synthesis process with a sintering‐free electrode fabrication technique. The as‐synthesized nanocomposite oxides self‐assemble into multiple phases, with GDC firmly grown on preformed NiO and NiFe ₂ O ₄ nanoparticles, which are subsequently in situ alloyed in a reducing atmosphere to form a unique NiFe@GDC encapsulation structure with strong metal–oxide interactions. This NiFe‐GDC nanocomposite not only provides abundant active sites for ammonia decomposition and electrochemical oxidation, but also exhibits exceptional resistance to nitridation and microstructural coarsening. Density functional theory calculations reveal that in situ‐formed NiFe alloy lowers the energy barriers for ammonia adsorption and dehydrogenation while enhancing the nitrogen desorption process. An electrolyte‐supported DA‐SOFC with the NiFe‐GDC nanocomposite anode achieves a peak power density of 0.61 W cm ⁻² at 800 °C and exhibits outstanding operational stability for 100 h. This work offers new insights into the development of active and durable nickel‐based nanocomposite anodes for DA‐SOFCs.