Energy storage systems are crucial for integrating renewable energy into the electricity grid. Redox flow batteries (RFBs) have become particularly promising for grid-scale storage due to their independently scalable energy and power, offering economic solutions for advancing sustainable energy infrastructure. As a core component, the porous electrode provides both active sites for redox reactions and pathways for mass and charge transport, largely affecting kinetic overpotentials, concentration overpotentials, and pressure drop during battery operation. Previous research studies have shown the importance of the material selection and electrode pore structure on the performance of the battery. However, the local mass transfer rates are largely influenced by the geometry of the electrode surface and the interaction of the fluid electrode with this surface. Traditional electrodes are based on cylindrical carbon fibers, but the precise geometry of the fiber varies depending on the manufacturing method and the post-treatment which can introduce roughness, porosity, or other features. The influence of the surface electrode geometry, and how this affects mass transfer rates have not been described in the literature. A deeper insight into the influence of the fiber morphology and an understanding of the local mesoscale transport phenomena can facilitate the design of electrodes with higher electrochemical performance. Computational modeling can provide such detailed insight without the need for time-intensive experiments that might enable controlled geometrical properties. In this research, we have developed a high-performance coupled framework for simulating pore-scale transport in porous electrodes in RFBs. The multi-physics computational model incorporates mass, momentum, and charge transport processes, including diffusion, advection, migration, and the Navier-Stokes and non-linear Butler-Volmer equations. The model was developed using the finite element method implemented using Firedrake and PETSc open-source codes. Various fiber shapes were considered to examine the effect of the morphology on the electrochemical performance. In this talk, I will first discuss the structure of the multi-physics modeling approach. Second, I will present the simulations performed with fibers having various etching/doping features in different shapes. Finally, I will discuss our findings on the correlations between fiber morphology and the local mass transfer profile.