Green Power Unleashed: Plant Extracts Forge Oxygen Bridges for Achieving Zinc-Ion Battery Super-Longevity

Abstract

The reversibility and cycling stability of aqueous zinc-ion batteries (AZIBs) are largely limited by the growth of zinc dendrites and side reactions on the anode. Herein, caulis polygoni multiflori extract (CPM) has been developed as an effective additive to improve the reversibility of AZIBs significantly. CPM preferentially adsorbs on the Zn surface, and sets up "oxygen bridges" between Zn plate and Zn2+ to capture Zn2+ through Zn and O coordination, effectively controlling the random diffusion of Zn2+ and inducing uniform Zn deposition. Additionally, the strong coordination between the oxygen-containing functional group and Zn2+ effectively reduces the binding of water molecules with Zn2+, which ultimately effectively suppresses the side reactions and hydrogen evolution. Consequently, the corrosion inhibition efficiency of the Zn was up to 97.2% at a CPM addition of 500 mg L-1, and the symmetric cell life was stable for 2900 h at 2 mA cm-2 and 2 mAh cm-2, and more than 1100 h at 8 mA cm-2 and 5 mAh cm-2. The Zn||MnO2 battery with CPM achieves a higher specific capacity and capacity retention after 1000 cycles. This work provides a new pathway for the development of green and efficient electrolyte additives to accomplish dendrite-free Zn anodes.

Keywords: electrolyte additives, Coordination capture, Plant extract, inhibit corrosion, Aqueous zinc-ion batteries.