Regulation and Stabilization of the Zinc Metal Anode Interface by Electroless Plating of a Multifunctionalized Polydopamine Layer

A novel electroless plating technique is utilized by coating a polydopamine layer on zinc foil (Zn@PDA) to regulate the deposition and growth of zinc dendrites, as well as suppress the occurrence of hydrogen evolution and passivation products for aqueous zinc-ion batteries. Polydopamine (PDA) has a strong adsorption ability on Zn foil due to the formation of a bidentate bonding during the electroless plating. Further, it indicates that the abundant hydroxyl groups of PDA react as zinc-philic sites to adsorb Zn2+ and further undergo redox by forming carbonyl groups to effectively induce the uniform deposition and growth of zinc dendrites. Meanwhile, the strong coordination of PDA and Zn2+ will weaken the solvated structure between Zn2+ and H2O molecules, resulting in an enhanced ionization energy of H2O and inhibited hydrogen evolution reaction. Thus, Zn@PDA can maintain stable cycling over 900 h at 0.2 mA cm-2, and a high coulombic efficiency of average 98.5% at 2 mA cm-2. Moreover, the validity of Zn@PDA has been verified using the Zn@PDA||self-standing VS2@stainless steel (VS2@SS) full battery, which displays an impressive capacity retention of 81.3% after 1000 cycles without sacrificing the rate performance. This work provides a simple, reliable, and harmless method to achieve high-performance aqueous zinc-ion batteries.