Intensified Flow and Mass Transfer in Lithium Slurry Redox Flow Batteries Enabled by a Bionic Leafvein Flow Field

Abstract

Lithium slurry redox flow batteries (SRFBs) are regarded as one of the most promising long-duration electrochemical energy storage devices as they combine the advantages of both traditional lithium-ion batteries and homogeneous flow batteries, while also offering the unique capability of decoupling energy density and power density. The flow field configuration of electrochemical reactors is critical for SRFBs as it can enhance flow distribution, reduce slurry retention, and improve mass transfer. Notably, the bio-inspired flow fields exhibit great application potential in SRFBs. In this study, we propose a bionic leaf-vein flow field based on a plant leaf vein model and Murray's law. In addition, a three-dimensional multi-physics field simulation model for SRFBs is established, with a verification error of less than 4% through charge-discharge experiments. The effects of the flow field on the slurry flow distribution, pressure drop, electrochemical reaction, battery impedance, and cycling performance are examined. The results reveal that the bionic leaf-vein flow field exhibits significantly lower flow resistance (with a pressure drop of 1.922 kPa) than the serpentine flow field (6.419 kPa). The flow area proportion increases from 0.8 without a flow field to over 0.93 with the proposed flow field. Furthermore, the SRFB can operate stably for more than 20 cycles while maintaining a high Coulombic efficiency (> 90%), significantly enhancing the battery performance.

Keywords: lithium slurry battery, multi-physics field simulation, bionic flow field design, flow distribution