Bifurcated interdigitated jet flow field: Overcoming hydraulic resistance in high-power flow batteries

Conventional flow fields in redox flow batteries (RFBs) face an intrinsic trade-off between limited mass transport and excessive pressure drops. To reconcile this conflict, a hydraulic-resistance-regulation strategy is proposed. Specifically, pressure drop contributions from channels and the porous electrode are theoretically decoupled via an equivalent hydraulic-resistance network model. Building on this model, a bifurcated interdigitated jet flow field (BIJFF) is designed to reconfigure the resistance distribution. In this flow field, bifurcated primary channels minimize channel resistance, while jet channels elevate the electrode's hydraulic resistance proportion from 13% to 32% to enforce strong under-rib convection. Modeling confirms that this optimized distribution reduces total pumping loss by 21% and improves species uniformity by 37% relative to conventional designs. In validation, the BIJFF-based flow battery demonstrates a high voltage efficiency of 81.1% at 240 mA cm⁻². This work provides unique insights into the active engineering of hydraulic resistance for high-performance flow batteries.