The Effect of Electrolyte Additives on the Performance of Iron Based Anodes for NiFe Cells

Aqueous electrolyte formulations for NiFe cells were prepared by using lithium hydroxide and potassium sulfide additives. The incidence of each additive on the overall performance of the NiFe cell was evaluated by cycling our in-house built bismuth sulfide based iron electrodes against commercially available nickel electrodes. In order to explore the composition space relevant to our formulations, a 12 replicates 3 × 4 full factorial experimental design was proposed to efficiently investigate the combined effect of both additives. Our experimental results suggest potassium sulfide enhances the performance of the battery. The role of lithium hydroxide is less clear but the evidence supports that it would increase coulombic efficiency to a lesser degree than potassium sulfide. This article demonstrates that by using a relatively simple manufacturing technique and low cost materials, it is possible to develop cost effective solutions to store large amounts of energy coming from renewables.