High Performance Zinc-Based Anodes for Aqueous Zinc Batteries

Abstract

In the past thirty years, there has been significant development in the search for alternative energy sources such as secondary battery systems. Zinc (fourth-most mined material) has attracted much attention due to its abundance, low-cost, and recyclability. Moreover, as zinc-based batteries can be manufactured with aqueous-based electrolytes that benefits from many advantages of Zn anode, such as low redox protentional (-0.76V vs SHE), high theoretical capacity (820mAh/g), and enhanced safety. These features allow for high applicability in large-scale stationary energy storage system. Zinc-based batteries (MnO2/Zinc) have been previously commercialized and are one of the dominant technologies in the primary battery market. However, the alkaline MnO2/Zn battery is not currently considered re-chargeable due to the formation of zinc-dendrites, passivation of Zn metal, and cathode poisoning. In contrast to the alkaline system, the mild acidic system does not suffer from zinc passivation as there is negligible generation of zinc oxide/zinc hydroxide.In this work, we report a proof-of concept work where electrodeposited zinc-based anodes (zinc and zinc-alloys) are used in mild acidic aqueous electrolyte. The study provides a comparison of commercial zinc foil, and electrodeposited zinc/zinc-alloy. The anodes are further analyzed structurally through X-ray diffraction and scanning electron microscopy. To evaluate the feasibility of each anode. further electrochemical characterization was carried out in coin cells as symmetric and full cells. The electrodeposited zinc-based anodes exhibit low electrode polarization (~0.030-0.045V), and more stable cycling performance at 10 mA cm-2 compared to commercial zinc foil. Furthermore, full cells with an electrodeposited zinc or zinc-alloy anode, DTT cathode, in 2M ZnSO4 delivered comparable capacities but higher stability compared to commercial zinc. Consequently, this work points toward a further development for anode materials in rechargeable aqueous zinc batteries for scalable applications.