A high volume specific capacity hybrid flow battery with solid active energy storage substance on the electrode

Redox flow batteries have gained significant attention in the context of large-scale energy storage systems, owing to their safety features, environmental sustainability, and the ability to decouple power generation from energy storage. However, the limited voltage and energy density of flow batteries pose challenges to their further advancement. In this work, we propose a novel hybrid flow battery that incorporates Ni(OH) 2 and hydrogen storage alloy respectively on the electrodes of Fe-DHPS flow batteries. This hybrid flow battery enhances the overall capacity of the battery while also mitigating the increased polarization often associated with the introduction of solid active substances into the tank. Additionally, it demonstrates a volume specific capacity of 60 Ah L −1 and an energy density of 65 Wh L −1 . Furthermore, these batteries demonstrate the capability to undergo 100 cycles at a current density of 60 mA cm −2 with a capacity decay rate of 0.3745 % per day. With the concentration of DHPS reaching theoretical solubility, the volume specific capacity can extend up to 120 Ah L −1 . This innovative flow battery, loaded with solid active substances on the electrodes, holds significant promise for large-scale energy storage systems.