Reversible Zn Metal Anodes Enabled by Trace Amounts of Underpotential Deposition Initiators

Routine electrolyte additives are not effective enough for uniform zinc (Zn) deposition, because they are hard to proactively guide atomic-level Zn deposition. Here, based on underpotential deposition (UPD), we propose an escort effect of electrolyte additives for uniform Zn deposition at the atomic level. With nickel ion (Ni2+) additives, we found that metallic Ni deposits preferentially and triggers the UPD of Zn on Ni. This facilitates firm nucleation and uniform growth of Zn while suppressing side reactions. Besides, Ni dissolves back into the electrolyte after Zn stripping with no influence on interfacial charge transfer resistance. Consequently, the optimized cell operates for over 900 h at 1 mA cm(-2) (more than 4 times longer than the blank one). Moreover, the universality of escort effect is identified by using Cr3+ and Co2+ additives. This work would inspire a wide range of atomic-level principles by controlling interfacial electrochemistry for various metal batteries.

Automated summary

Routine electrolyte additives are not effective enough for uniform zinc (Zn) deposition. Based on underpotential deposition (UPD), an escort effect of electrolyte additives for uniform Zn deposition at the atomic level is proposed. With nickel ion (Ni2+) additives, metallic Ni deposits preferentially and triggers the UPD of Zn on Ni, facilitating firm nucleation and uniform growth of Zn while suppressing side reactions. The optimized cell operates for over 900 h at 1 mA cm(-2), more than 4 times longer than the blank one, indicating the significance of this work.