Laser perforated porous electrodes in conjunction with interdigitated flow field for mass transfer enhancement in redox flow battery

To further enhance the efficiency of redox flow batteries, there is a vital need to decouple the conflict between specific surface area and hydraulic permeability in porous electrodes. In this work, we propose a facile and highly productive method to devise porous electrode's pore structure in conjunction with the flow field topology based on the infrared laser perforation to reconcile the combination of large and small pores. We find experimentally that the method of perforation under the center of the rib yields a significant improvement on the overall performance, with an increase in the maximum power density by approximately 2.4 times compared to that without the perforation. We also devise a pore-network model, by using which we explore the effects of large pores formed by the laser perforation on the distributions with respect to the local velocity, active species concentration and reaction rate, as well as the effects of the perforation location and diverse operating conditions on flow cell's overall performance. The results show that under the general operating conditions of the VRFB, we recommend to produce large pores in the region under the rib close to the outlet channel to enable substantial performance gains.