Study of the Properties of Iron/Iron Redox Flow Batteries

Abstract

New energy storage technologies are needed to offset the erratic power supply of renewable energy sources due to the rising global energy demand and the urgency of climate change action. Even if there are still concerns with operational parameters and efficiency, the Iron/Iron redox flow battery is a viable contender for large-scale energy storage. Iron is a highly affordable active material, making it possible to create inexpensive energy storage systems and possibly batteries with very low initial investment costs due to the positive electrode's moderate pH and relatively low voltage, maintaining minimal toxicity and aggression. Many challenges have been faced in the experiments on iron/iron redox flow batteries. For example, hydrogen formation and its impacts on the system must be minimized to ensure long-term use as an energy storage device. Iron hydroxides quickly form in response to elevated pH levels or contact with ambient oxygen, which restricts the battery's effectiveness.For each series, various iron/iron redox flow batteries were assembled, and their functional properties were studied as a sustainability factor. The functional properties of the battery, such as an increase in electrolyte volume, an increase in charge/discharge times, the addition of a break time between charge/discharge cycles, varied charge cut-off voltages, varied discharge cut-off voltages and IU charge/discharge were investigated. It was also possible to complete more than 50 cycles with 8 hours of charging time and calculate and compare efficiencies and other performance values. The 8 hours of charge/discharge parameter proved to be the most suitable for conducting long-term cycling experiments because of the increased CE and EE trendline over 25 cycles. The 60 minutes rest time recorded a delay of charge voltage with a maximum of 35 minutes starting from the third cycle because of the blockage of the membrane and polarization effects. An optimized battery achieved up to 62% energy efficiency at 25 mA/cm2 with 4 hours of charging time and 8.01 Ah maximum theoretical capacity. Figure 1