In-plane gradient design of flow fields enables enhanced convections for redox flow batteries

Abstract

In the realm of redox flow batteries, the flow field plays a vital role in influencing the overall performances of the redox flow batteries. Inspired by human behavior, an in-plane gradient flow field design featuring a gradient decrease in channel width from the inlet to the outlet is proposed in this work. A three-dimensional multi-physical simulation model was utilized to investigate the transport behaviors and overall battery performance associated with novel flow field configurations. It was indicated that the novel in-plane gradient design can enhance the under-rib convections of the electrolyte in the downstream regions near the outlet, leading to improved uniformity of the active species’ distribution over porous electrodes. Consequently, this enhancement substantially reduces concentration polarization losses of redox flow batteries. The maximum power density and rated current density of the proposed design are 553.2 mW cm⁻² and 270.1 mA cm⁻², which are 74.5 mW cm⁻² and 8.3 mA cm⁻² higher than conventional design. These results substantiate the benefits of employing the proposed flow field for achieving high-performance battery designs. Meanwhile, due to its straightforward, efficient, and easily scalable design mechanism, this novel flow field shows great promise for engineering applications of redox flow batteries.