Embroidered porous electrodes for reduced pressure drop in vanadium flow batteries

Vanadium flow batteries (VFBs) are highly regarded for their significant potential in large-scale energy storage systems. However, their operational efficiency is hindered by the persistent issue of energy losses resulting from pressure drop in the porous electrodes. Herein, we present a strategy to reduce pressure drop and augment the overall energy efficiency of VFBs by using an embroidery technique, crafting diamond, parallel, and perpendicular patterns on carbon electrodes. Complemented by a hydraulic model, this strategy refines flow dynamics. Results show embroidered electrodes achieved pressure reductions of 36.0 %, 39.0 %, and 12.0 % for diamond, parallel, and perpendicular designs respectively, compared to unmodified electrodes. Furthermore, the diamond pattern evinced a substantial enhancement of 5.5 % - including pumping loss - over the pristine felt electrode at varying current densities. Additionally, the hydraulic model suggests that using a 0.3 mm channel width and 3 mm spacing in parallel and diamond patterns led to pressure drop reductions of 71.6 % and 73.5 % compared to the unmodified carbon electrode. Our study demonstrates the promising potential of embroidered porous electrodes for VFBs as a viable solution for reducing pressure drop and enhancing energy efficiency.