Gradient porosity anodes for enhancing the electrochemical and thermomechanical performance of methanol-fueled SOFC

Abstract

During practical operation of methanol-fueled solid oxide fuel cell (SOFC), the endothermic reforming induces large temperature gradients and high first principal stress, accelerating cell degradation. To improve the thermomechanical performance of methanol-fueled SOFC, gradient-porosity anodes are proposed in this work. A multi-physics coupled model for single-channel methanol fueled SOFC is developed, with current density, temperature gradient and maximum first principal stress as evaluation indicators. The performance of homogeneous anodes (porosity 0.2–0.4) is first investigated. The results indicate that anode porosity affects cell performance by regulating electrical conductivity, gas diffusion, and thermal conductivity, but homogeneous anodes cannot balance electrochemical and thermo-mechanical properties. Accordingly, gradient-porosity anode along the height, length, and width directions of the cell are investigated. The results show that the width-direction gradient anode exhibits optimal comprehensive performance. It reduces the maximum first principal stress by 14.48% and 16.89% under co-flow and counter-flow conditions, with only 3.00% and 1.38% loss in current density. Multi-condition comparisons confirm that the gradient anode effectively improves the thermomechanical performance while maintaining stable electrochemical performance. This study provides a feasible approach for enhancing the thermo-mechanical performance of methanol-fueled SOFC through microstructure optimization.