Although the results of the topology optimization algorithms were non-trivial for both 2D and 3D cases, the performance analysis showed that the optimized designs perform significantly better than a uniform-porosity electrode in terms of ohmic and pumping power losses. We obtained designs with the flow pathway formed along the ionic channels, resembling an integrated flow field inside the electrode. In all simulated cases, the pumping power loss, expressed as the power dissipation across the electrode, was reduced by 61% -98% depending on the operating conditions and the defined Darcy number. For electrochemical performance, an improvement up to 29% was observed, although in some cases the electrochemical performance decreased by down to 12% due to the formation of a low hydraulic resistance bypass channel. In the optimized designs, both the electrochemical and pumping power optimizations compete to reduce the corresponding losses by forming the conductive and flow bypass channels, respectively. Depending on the operating conditions and applied properties, the flow pathway would emerge in different regions of the electrode. By fixing the relative importance of ohmic and kinetics losses, the flow pathway formed in the vicinity of the membrane under high liquid/solid conductivity ratio. On the contrary, when the ratio of liquid/solid conductivity is low, the flow pathway emerged in the middle of the electrode. Increasing applied current density showed to increase the portion of liquid phase to provide the reactions needed for the applied current when the kinetics are not limiting. Similarly, in the 3D case under high applied current density, the optimization algorithm created two flow pathways in order to add more liquid to satisfy the applied current density.