Zinc-nickel batteries (ZNBs) are promising green energy storage devices. However, ZNBs employing traditional strong alkaline aqueous electrolytes are plagued by dendrite formation, corrosion, shape change, and electrolyte dehydration, which severely hinder their wider application. To overcome such obstacles, introducing sodium polyacrylate (PANa) and trimethyloctadecylammonium chloride (STAC) as electrolyte additives is proposed. The PANa-based electrolyte can maintain sufficient moisture in a high-concentration KOH environment and a high ionic conductivity. Additionally, the zincophilic STAC cation adsorbs on the protrusions, inhibits shape changes, promotes lateral growth, and forms a noticeably smooth and dense Zn anode. Therefore, the ZNBs assembled with PANa and STAC additives in the electrolyte have an impressive cycle life of 1168 h at a current density of 66.7 mA cm