ORALS

Aqueous zinc ion batteries (AZIBs) have emerged as one of the promising next-generation secondary batteries, offering affordability and inherent safety features. However, AZIBs face limitations associated with the use of water-based electrolytes, which result in low operating voltages and subsequently low energy density. Additionally, challenges such as dendrite growth and hydrogen gas evolution at the interface between the zinc metal anode and electrolyte further hinder the commercialization of AZIBs. To address these issues, this study focuses on implementing two interfacial modification strategies. In the first study, we tried to enhance the depth of discharge (DOD) by using a zinc powder electrode instead of thick zinc foils as the anode, thereby reducing the N/P ratio. However, the high surface area of zinc powder accelerates dendrite growth and corrosion. To address these challenges, we applied a uniform SnO2 coating layer on the zinc powder using the atomic layer deposition (ALD) technique. The SnO2 coating effectively inhibits dendrite growth and corrosion on the zinc powder surface. When we implemented this interfacial modification strategy in a full-cell configuration, we observed an increase in discharge capacity from 163 mAh g-1 to 221 mAh g-1, indicating improved cycling performance. Ultimately, by using zinc powder anodes with a low N/P ratio similar to that of commercial lithium-ion batteries. As a result, by applying SnO2 coating as a protective layer, we not only increased the zinc utilization rate but also achieved an increase in volumetric energy density. Secondly, we introduced tetrabutylammonium iodide (TBAI) as an electrolyte additive to the mildly acidic ZnSO4 electrolyte. This approach combines the zincophobic repulsion effect of cationic TBA+ ions and the corrosion inhibition effect of the anionic I- ions. TBA+ ions form a protective layer on the zinc anode surface, preventing localized deposition of Zn2+ ions. I- ions act as corrosion inhibitors, suppressing the detrimental corrosion at the interface. By effectively addressing these issues at the interface, we achieved improved capacity retention in the full-cell system with a Zn0.25V2O5 cathode. After 5000 cycles, the capacity retention rate increased from 44.7% to 58.3% upon the incorporation of the TBAI additive.