A qualitative comparison with the work of Beck et al. was made for 2D simulations in Section 3.1.1, but a quantitative comparison is possible for the 3D simulations only since their model was developed in 3D. In the current study, the electrical performance enhancement was 3% and 16% for the case (A) and (B), respectively. Comparing the electrical losses according to the internal resistance between uniform-porosity and optimized samples in Beck et al. work shows an improvement of ∼ 7-20%, which is in agreement with the obtained results especially for the low current density case. Moreover, the performance improvement in terms of pumping power is 40% for both cases (A) and (B), which is in agreement with the flow power losses reported by Beck et al. (∼ 40 -50%).