Research Progress and Prospect of All-Iron Redox Flow Battery Anolyte.

The all-iron redox flow battery (AIRFB) has garnered significant attention in the field of energy storage due to its advantages of cost, aqueous chemistry, safety, and sustainability. The traditional deposited AIRFB has a limited depth of discharge and is prone to metal dendrite growth and hydrogen evolution side reactions during operation. In contrast, the all-soluble AIRFB, where the active substances are all fully soluble, offers flexible operation that is more conducive to industrial development of AIRFB. However, the all soluble AIRFB electrolyte still requires improvement of its solubility, long-term stability, reactivity, and electrode potential. This review introduces the concepts for modification of the AIRFB electrolyte and presents the main ideas and methods for electrolyte improvement, as well as the challenges faced and possible research directions for the future.