Disodium Malate Electrolyte Additive Facilitates Dendrite-Free Zinc Anode: Deposition Kinetics and Interface Regulation.

Due to the presence of HO within the solvated sheath of [Zn(HO)] as well as reactive free water in the electrolyte bulk phase, the extended cycling of aqueous zinc-ion batteries (AZIBs) is significantly affected by detrimental side reactions and the growth of Zn dendrites. This study significantly enhances the long-term cycling stability of AZIBs by introducing a small amount of disodium malate (DM) into a 2 m ZnSO electrolyte solution. DM involvement in the solvation sheath of Zn reduces the desolvation energy of Zn, thereby mitigating the corrosion and hydrogen evolution reaction (HER) of the negative electrode surface by [Zn(HO)] ions. Additionally, DM adsorption on the zinc surface retards the reduction kinetics of Zn at anode, promoting uniform distribution and predominant deposition on the flat (002) crystal plane, thus reducing dendrite formation. The assembled Zn||Zn symmetric cell exhibits stable cycling for over 500 h at 10 mA cm and 5 mAh cm. The Zn||VO full cells with DM additive exhibits an ultralong cycling lifespan without capacity loss.