Ammonia-fed proton- and oxygen-ion conducting solid oxide fuel cells: Performance, technoeconomic analysis and multi-objective optimisation

Ammonia is a promising hydrogen carrier with significant advantages in storage and transport, offering an attractive pathway for zero-emission power generation. This study evaluates the performance, thermal behaviour, and economic feasibility of ammonia-fed solid oxide fuel cells (SOFCs) employing proton-conducting electrolytes (SOFC-H) and oxygen-ion-conducting electrolytes (SOFC-O) under co-flow (fuel and air flowing in the same direction) and counter-flow (opposing flow directions) configurations. A comprehensive model integrating electrochemical, thermal, and techno-economic analyses was developed. To reduce computational cost, Latin Hypercube Sampling (LHS) and Artificial Neural Network (ANN)-based surrogate models (R² > 0.9999) were combined with NSGA-II for multi-objective optimisation of the Levelised Cost of Electricity (LCOE) and maximum temperature gradient. SOFC-H in counter-flow achieved the best performance, reaching a peak current density of 10,966 A m - ² and a minimum LCOE of 0.28 $ kWh -1 . Optimised configurations selected via the TOPSIS method yielded a balanced trade-off: an LCOE of 0.32 $ kWh -1 with a 72% reduction in temperature gradient (2.65 °C cm -1 ). In comparison, SOFC-O configurations remained 30–33% more expensive than Australia’s average electricity cost (0.27 $ kWh -1 ). The sensitivity analysis identified ammonia price as the dominant cost factor, with SOFC-H systems showing greater economic resilience. This study demonstrates that combining advanced modelling with surrogate-assisted multi-objective optimisation enables the design of efficient and cost-effective ammonia-fed SOFC systems, offering a viable pathway for clean energy transition globally.