Harmonized Multifaceted Zinc Deposition Enabled by Amine‐Functionalized Carbon Quantum Dots for Dendrite‐Free Zinc Anodes Under Ultrahigh Current Densities

Dendrite formation continues to inhibit the development of aqueous zinc‐ion (Zn 2+ ) batteries (AZIBs). A common strategy for suppressing Zn dendritic growth is to promote Zn 2+ selective deposition along the (002) plane, which features a smooth and uniform atomic arrangement. However, this strategy is most likely to break down at high current densities (> 40 mA cm −2 ) because Zn 2+ elsewhere cannot rapidly diffuse to the (002) plane for deposition. The resulting excessive electron accumulation then boosts the electronegativity of other planes, readily disrupting the engineered (002)‐preferred deposition. Herein, to overcome this issue, amine‐functionalized carbon quantum dots (NH 2 ‐CDs) have been developed as an electrolyte additive. Surface‐rich NH 2 groups on water‐soluble CDs provide stronger Zn 2+ affinity than H 2 O, forming uniform Zn 2+ –NH 2 ‐CD complexes, which exhibit similar adsorption energies on the three major planes of Zn foil. This functionality, for the first time, realizes multifaceted Zn 2+ deposition along the native crystal planes of Zn foil, suppressing dendrites even at ultrahigh current densities. Consequently, Zn||Zn cells with NH 2 ‐CDs as an electrolyte additive achieve a cumulative capacity of 5000 mAh cm –2 at 100 mA cm –2 . Our work pioneers a novel strategy for dendrite‐free Zn anodes under ultrahigh current densities, highly advancing the development of practical AZIBs.