Boosting ultra-long cycling and shelf life of nickel−zinc battery via guiding oriented zinc deposition and suppressing [Zn(OH)4]2− diffusion

Alkaline nickel−zinc (Ni−Zn) battery has been considered as a competitive candidate for the application of uninterrupted power supply and grid energy storage due to the intrinsic safety and impressive power density. However, the application of the Ni−Zn battery is restricted by the self-corrosion and uneven deposition of the zinc anode. Herein, polyethylene glycol (PEG-300) is introduced into the electrolyte to form a protective layer by preferential adsorption on the zinc anode, which can inhibit the tip effect and limit the lateral diffusion of [Zn(OH)4]2−. Moreover, the long-chain molecules of PEG suppress the [Zn(OH)4]2− diffusion from the surface of zinc anode to the bulk electrolyte, thereby inhibiting the self-corrosion. Therefore, the assembled practical battery with 2 % PEG additive demonstrates an ultra-long cycling life under deep discharge depth (∼700 cycles) or large current density (∼10450 cycles), and can even successfully support the 1500 W elevator automatic rescue device (ARD) system to running for 5 min. Furthermore, PEG as an effective and scalable electrolyte additive is expected to promote the practical application progress of the Ni–Zn battery for the next generation energy storage device.