Innovative Electrolytic Production of Iron Powder for the Circularity of Iron Fuel Cycle

Renewable energy intermittency demands efficient storage solutions. Iron powder is proposed as a promising candidate for energy carriers due to its high energy density, abundance, and transportability. Energy is released by the combustion of iron powder, yielding iron oxides that can be easily collected and reduced back to metallic iron – a process termed the iron fuel cycle. Electrochemical reduction of iron oxide in alkaline media offers a carbon-neutral and low-temperature/energy approach for this reduction process [1]. In the previous study, we proved that electroreduction with dendrite-rich structures can facilitate easier harvesting and conversion of electrolytic iron deposits to powder form [1-2]. The present study reports the design and performance of an electrochemical reactor featuring a rotating disc system, tailored for continuous electrolytic iron powder production. The reactor combines the electroreduction process from the iron oxide reduction process to subsequential steps (cleaning, drying, and dendrite/powder harvesting), offering an integrated and automated solution [3]. Proof-of-concept experiments demonstrate the feasibility of producing iron deposits with dendritic structures under various conditions. Dendritic iron growth at the disc's edge enhances harvesting and conversion to iron powder where current efficiencies of 85-90% are achievable [4-5]. Analysis using a scanning electron microscope (SEM) also reveals the deposit microstructures under various conditions. This research advances the understanding of (iron oxide) “powder-to-powder” (iron) electroreduction for the circularity of the iron fuel cycle and introduces innovative powder production techniques for sustainable iron/steel-making technologies.