Design and performance optimization of a direct ammonia planar solid oxide fuel cell for high electrical efficiency

Abstract

Achieving higher efficiency of direct ammonia solid oxide fuel cells (DA-SOFC) requires high compatibility between cell design and temperature distribution during NH3 decomposition. Therefore, this work aims to provide a comprehensive study of the DA-SOFC different design configurations and parameter optimization. Three main flow configurations are co-flow, counter-flow, and cross-flow. In addition, a detailed parametric study of the cross-flow configuration is performed to optimize cell performance by minimizing thermal stress, considering thermal management, efficiency, and manufacturing advantages. The model is experimentally validated, and the mean relative error and root mean square error is found to be less than 2%. The co-flow configuration has shown lower power output at higher current densities than the counter and cross-flow configurations. At the same time, co-flow possesses minimum thermal stress across the cell cross-section. In cross-flow design, the maximum electrical efficiency of 51.4% with 152 K cell temperature difference is established at 60% fuel utilization, 3% air utilization, fuel intake temperature, and air inlet temperature at 923 K. This study is expected to help optimize the design and operating parameters to maximize DA-SOFC stacking performance and durability and minimize cost.