(Digital Presentation) Understanding the Electrochemical Stability of Potential Current Collectors in Zinc Sulfate Electrolyte for Rechargeable Aqueous Zinc Ion Battery Application

Abstract

The need for clean and sustainable energy sources has witnessed a sudden upsurge in recent years owing to rising environmental degradation and climate disruption brought on by an overdependence on fossil fuels [1-3]. Electrochemical energy conversion technology is a crucial complement to the storage and on-demand utilization of renewable energy resources [4-6]. Rechargeable aqueous zinc ion batteries (AZIBs) have gained a significant research upsurge in recent times owing to their attractive potential for large-scale energy storage applications. In addition to low cost and naturally abundant raw materials, AZIBs technology offers competitive electrochemical performance and compatibility with water-based electrolyte systems, thereby eliminating the safety concerns associated with prevalent lithium-based battery technology. Moreover, multivalent AZIBs offer the opportunity to attain high energy and power density by permitting multiple electron transfers during reversible electrochemical operations [7]. In the context of AZIBs, significant research efforts are being actively pursued to develop high energy density cathode materials and to address the issue of Zn dendrite formation [8]. However, the selection of stable and low-cost current collectors is equally important as it serves as a bridge between the battery components and the external circuit, thereby influencing the battery capacity and its rate capability [9-10]. In this work, we have analyzed the electrochemical behavior of potential current collectors that are used globally in battery applications, namely Ni, Al, carbon paper, Cu mesh, graphite, and stainless steel in near-neutral aqueous ZnSO4 electrolyte (pH value = 5-6). The electrochemical stability of different current collectors has been investigated using linear sweep voltammetry and chronoamperometry techniques for their application as anode and cathode collectors. Scanning electron microscopy analysis has also been performed to understand the sign of corrosion post-electrochemical study. With stability up to 2.3 V w.r.t. Zn/Zn2+, Ni has proved to be the most corrosion-resistant current collector among the tested collectors on the cathode side. Although Zn itself is sufficiently stable at the anode side than any other current collector under the ZnSO4 electrolyte environment, Ni has shown considerable stability. Nonetheless, understanding the electrochemical stability of current collectors for AZIBs is a vital step in their design and future practical applications.