Towards improving the performance of the negative Zn electrode in Zn-Ion batteries

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Rechargeable Zn-ion batteries are targeted for non-portable applications, such as grid-scale energy storage, and provide several advantages over the Li-ion batteries currently used for these applications, including safety due to the aqueous electrolytes employed, while relying on Zn that is inexpensive, non-toxic and mined/produced within Canada. Salient Energy's Zn-ion batteries consist of: (i) negative Zn electrode where direct plating and stripping of Zn occurs; (ii) near-neutral aqueous Zn sulphate electrolyte, complete with a separator; and (iii) positive electrolytic MnO2 electrode capable of reversibly intercalating divalent Zn cations. Having successfully addressed problematic preferential (dendritic) Zn growth during plating/stripping at the negative electrode, which serves to short-circuit the battery, Salient Energy now faces a new challenge with the negative Zn electrode: parasitic corrosion reactions (self-corrosion) that limit cycle life and produce hydrogen gas. The overarching research objective is to determine the cause of the parasitic self-corrosion that occurs during cycling of the battery at the negative Zn electrode. This will be achieved through the three research sub-objectives: (i) characterize the corrosion damage accumulation on negative electrodes removed from scaled-up batteries, (ii) determine the corrosion mechanism of Zn metal in near-neutral aqueous Zn sulphate electrolytes, and (iii) determine the galvanic corrosion susceptibility of the Zn-brass couple that is intrinsic to the laminated negative electrode assembly. The project will create new knowledge that is required for novel science-based corrosion control strategies to be identified and evaluated. The project will train one PDF for the two year Missions Grant project.