A nuclei-rich strategy for highly reversible dendrite-free zinc metal anodes

Abstract

Aqueous zinc (Zn) metal batteries are promising candidates for large-scale energy storage owing to their low cost and high safety. However, dendrite formation on Zn metal electrodes leads to short circuits and low coulombic efficiency. Zinc deposition tends to grow into large hexagonal plates with sharp corners and edges. To address this, we propose nuclei-rich Zn plating in which nucleation is promoted over growth to achieve dendrite-free cycling. By fabricating a hydroxyapatite-based nuclei-incubating interface with high ion conductivity and nucleation catalytic activity on the Zn surface, the plating reaction of Zn is fundamentally modified to persistently generate a large number of nuclei that grow into densely packed Zn crystals with small radii and high uniformity. Owing to this high-rate progressive nucleation strategy, the nuclei-rich Zn electrode enables stable cycling for over 1200 h with a coulombic efficiency of 99.7% under the harsh conditions of 10 mA h cm⁻² areal capacity at 15 mA cm⁻², based on which a Zn–MnO₂ full cell with a low N/P ratio of 1.9 and a long cycle life of 3000 cycles is demonstrated. This strategy highlights the profound impact of the growth mechanism on metal morphology and can be applied to address dendrite issues in other metal electrodes such as lithium.