Enhanced Zn plating and stripping behavior of the utilized fly ash-coated Zn anode for zinc-ion batteries

Rechargeable aqueous Zn-ion batteries (ZIBs) have emerged as a promising new energy storage technology, characterized by their low cost, high safety, environmental friendliness, and the abundant availability of Zn resources. However, several challenges remain with their use, such as zinc dendrite formation, corrosion, passivation, and hydrogen evolution reaction (HER) on the zinc anode surface, leading to a short overall battery life. In this paper, a zinc anode-coating method with silica-fly ash composite (FAS) has been developed. This modified Zn anode (5FAS@Zn) demonstrates remarkable improvements in the performance and stability of ZIBs by effectively decreasing zinc nucleation overpotential and minimizing charge transfer resistance while facilitating stable Zn plating and stripping as well as achieving even zinc deposition. The remarkable cycling lifespan of the 5FAS@Zn||5FAS@Zn symmetrical cell is 1800 h at 0.5 mA cm⁻² and 1500 h at 1 mA cm⁻². The 5FAS@Zn||Cu half-cell outperforms pure Zn batteries with a high and consistent Coulombic efficiency (CE) of 99.8% over 800 cycles at 1 mA cm⁻². Furthermore, the full cell of 5FAS@Zn||V₂O₅ exhibits notable improvements in cycling performance. This research provides a scalable and sustainable method to extend the life of zinc anodes and has significant implications for the large-scale deployment of zinc-ion batteries.