Electrochemical Stability of Prospective Current Collectors in the Sulfate Electrolyte for Aqueous Zn-Ion Battery Application

Research on aqueous Zn-ion batteries has witnessed a tremendous upswing in recent years owing to their attractive prospect for large-scale storage applications. While high energy cathode materials development and the zinc dendrite issue is being intensively pursued, the electrochemical stability of the current collector materials - which support the electrode film - in aqueous electrolytes is rarely pondered. It would not be an overstatement to say that the electrochemical stability of the collectors is taken for granted. In this study, we probe a range of prospective current collector materials that are commonly employed, namely Ti, Ni, stainless steel (304 and 316), Cu, Al, graphite, and carbon paper, and investigate their stability to electrochemical corrosion for use as the cathode and anode collector by linear sweep voltammetry and chronoamperometry in the aqueous sulfate electrolyte. Ti stands out as the most corrosion resistant current collector for the cathode side with stability over 3 V against Zn, but Ni, graphite, carbon paper, and stainless steel are considerably stable in that order. While Zn itself is much more inert than any of the current collector materials for the anode side, Ti has acceptable stability. Nonetheless, detailed insights are provided on the electrochemical stability regime of the investigated materials, which will be useful while considering the choice of the current collector or cell component for AZIB studies and their future development.