In this work, a novel hybrid flow battery system is proposed. In the negative side, we explore a vitamin-based molecule that has never been tested in a flow battery before. As a quinone derivative, it undergoes a reversible two-electron redox reaction at 0.05 V vs. standard hydrogen electrode. The solubility of the molecule is higher than 4.5 M, leading to a volumetric energy density of 120 Wh/L, when paired with a lead dioxide/lead sulfate electrode [1]. Such a hybrid flow battery achieves a cell voltage of 1.68 V and can be cycled stably for over 50 cycles without significant capacity loss. The adoption of solid-state lead-based electrode eliminates the need of an expensive ion exchange membrane. More importantly, as the molecule has been mass-produced at low cost, the cost of this novel system is much lower than current existing flow battery systems [2-3]. It is a promising candidate for both large scale energy storage usages and mobile applications in both perspectives of cost and energy density.

[1] Leung, P. K., Qian Xu, and T. S. Zhao. "High-potential zinc–lead dioxide rechargeable cells." Electrochimica Acta 79 (2012): 117-125.

[2] Zhang, Mengqi, et al. "Capital cost sensitivity analysis of an all-vanadium redox-flow battery." Journal of The Electrochemical Society 159.8 (2012): A1183-A1188.

[3] Zeng, Y. K., et al. "A comparative study of all-vanadium and iron-chromium redox flow batteries for large-scale energy storage." Journal of Power Sources 300 (2015): 438-443.