Numerical investigation of coupling effects of gradient porous electrode and flow channel pattern on iron-vanadium redox flow battery

As a crucial component of redox flow batteries (RFBs), porous electrode provides active sites for redox reaction to realize electrochemical energy conversion. The coupling reaction kinetics and mass transfer process of active materials in porous electrode have great impact on the battery energy efficiency. As pore structure of porous electrode and its internal electrolyte flow regime jointly determine the convective mass transfer properties and electrochemical reaction efficiency in RFBs, based on the existing studies about the gradient porous electrode and the developed flow channel structure in recent years, this paper aims to investigate the coupling effects of gradient porous electrode and flow channel pattern on the mass transfer process in electrodes and the electrochemical performance of RFBs. A macroscopic three-dimensional model on non-aqueous iron-vanadium flow battery is established according to the actual operation characteristics of RFBs by finite element method. The numerical results reveal the operation process properties of iron-vanadium flow battery affected by the different flow field and gradient structural porous electrode, thus obtaining the optimal flow channel pattern and gradient morphology of porous electrode to improve the cell performance.