Abstract
In this study, we propose a computational methodology to optimize the microstructure of the carbon felt electrode employed in redox flow batteries. Our optimization objective is to maximize the electrolyte utilization rate, which is affected by the fibrous electrode’s microstructure, in addition to the properties of the active species. The active surface area for the electron transfer process depends on the electrode microstructure, which is also critical for the convection of the electrolyte flow. By combining the stochastic generation of the electrode microstructure, the digital compression of the electrode, the Lattice Boltzmann Method, and the Bayesian optimization approach, we established our computational workflow that predicts an optimized set of parameters for electrode design. The optimization results demonstrate that a high compression ratio with thick aligned fibers favors better electrode performance. For a highly compressed felt electrode, the pore size generally decreases while a small amount of large-sized pores remain in the structure, facilitating the convection in the electrolyte flow. Due to the heterogeneous distribution of pores in the compressed felt electrode, the specific surface area and the hydraulic permeability are balanced to an optimized point.