Multifunctional Nanodiamond Interfacial Layer for Ultra-Stable Zinc-Metal Anodes

Achieving reversible plating/stripping of zinc (Zn) anodes is crucial in aqueous Zn-ion batteries (AZIBs). However, undesired dendrite growth and parasitic side reactions severely deteriorate battery lifespan. The construction of stable protective coating is an effective strategy to enhance anode stability. In this study, a multifunctional nanodiamond (ND) inorganic layer is designed and constructed on both Zn and Cu electrodes that can both effectively inhibit dendrite growth and suppress Zn anode corrosion. Experimental results and theoretical calculations demonstrate that this artificial protective layer, with ultra-high surface energy, enables the controlled creation of abundant nucleation sites (in the order of 10¹² cm⁻²) for the homogenization of ion flux and electric field on the anode. It is found that zinc ions preferentially adhere to the diamond surfaces with lower diffusion barriers, leading to uniform zinc deposition. A symmetric cell with the ND-protected Zn (Zn-ND) anode exhibits reversible plating/stripping behavior for an impressive duration of over 3600 h at 1 mA cm⁻². Furthermore, the MnO₂||Zn full battery retains 90% of its initial capacity after 3500 cycles at 2 A g⁻¹, and assembled hybrid capacitor operates smoothly over 65 000 cycles at 10 A g⁻¹. These results underscore the potential of this coating as a promising solution for achieving highly stable Zn anodes for aqueous batteries.