Slurry Based Lithium-Ion Flow Battery with a Flow Field Design

Abstract

Slurry based lithium-ion flow battery has been regarded as an emerging electrochemical system to obtain a high energy density and design flexibility for energy storage. The coupling nature of electrode thickness and flow resistance in previous slurry flow cell designs, demands a nuanced balance between power output and auxiliary pumping. To address this issue, a slurry based lithium-ion flow battery featuring a serpentine flow field and a stationary porous carbon felt current collector is proposed in this work. The carbon felt serves to provide a stable and efficient pathway for electron transport, while the flow field helps distribute active slurry onto the felt for electrochemical reactions. With such a design, the LiFePO4 (LFP) slurry based flow battery shows a low flow resistance and good flow stability without forming severe filter cakes on the felt surface, similar to cross-flow filtration. A maximum power density of 84.5 mW cm−2 and a stable coulombic efficiency of ∼98% under intermittent flow, and a specific capacity of 164.87 mAh g−1 (based on the total LFP in the tank) in continuous flow are successfully demonstrated. These preliminary yet encouraging results may put forward new avenues for future structural design and optimization of slurry based flow batteries.