Analysis of Electrode Configuration Effects on Mass Transfer and Organic Redox Flow Battery Performance

For organic redox flow batteries (ORFBs), it is of significance to clarify the influence mechanism of their electrode configuration on the mass transfer inside electrodes and battery performance. A novel three-dimensional (3D) numerical model for ORFBs is established based on the Nernst–Planck and Butler–Volmer theories and is verified by numerous experiments for both the charge and discharge processes. ORFBs equipped with rectangular, trapezoidal, and sector electrodes are investigated, in which the voltage, overpotentials, uniformity factor, and the power efficiency of the discharge process are presented. The results show that the sector electrode possesses the best mass transfer and battery performance. The power-based efficiency of the sector electrode is 1% higher than that of the trapezoidal one. In addition, the opening angle of the sector electrode should be as small as possible. The optimal aspect ratio of the rectangular electrode is 60:107, and the optimal configuration of the trapezoidal electrode is 30 mm top side length and 130 mm bottom side length. The optimization of the porous electrode configuration is presented, which can contribute to the commercial application of ORFBs.