Cost‐Effective Passive Ammonia Fuel Cells via Synergistic Integration of Optimized Membrane Electrode Assembly and Prototype

Abstract Passive ammonia fuel cells (PAFCs) offer modular adaptability but face dual challenges: limited power density and dependency on noble metals. Here, a comprehensive strategy is presented to address these issues through coordinated materials and system design. Pre‐oxidized nickel substrates direct the formation of β‐phase NiOOH/Ni 3 P (β‐NiOOH/Ni 3 P) heterointerfaces in anode, significantly enhancing ammonia oxidation reaction (AOR) kinetics with a high current density of 171 mA cm −2 at 0.7 V. A spinel‐structured MnCo 2 O 4 /C cathode catalyst demonstrates remarkable ammonia tolerance and outperforms Pt/C in stability. A polytetrafluoroethylene/layered double hydroxide (PTFE/LDH) composite membrane is also introduced, which effectively reduces ammonia crossover. Their integration with an optimized graphite prototype further enhances PAFCs' efficiency and stability. This synergistic multi‐phase optimization enables record‐breaking performance for non‐noble metal‐based PAFCs, achieving a peak power density (PPD) of 61 mW cm −2 and an open circuit voltage (OCV) of 0.87 V (outperforming Pt‐based PAFCs). Stable discharge can be sustained by the present PAFC for 9 h by replenishing the ammonia supply. This work establishes a prototype‐to‐performance strategy for cost‐effective PAFC, highlighting the potential of non‐noble metal catalysts in ammonia electrochemical energy conversion.