Mosaic Nanocrystalline Graphene Skin Empowers Highly Reversible Zn Metal Anodes

Abstract

Constructing a conductive carbon-based artificial interphase layer (AIL) to inhibit dendritic formation and side reaction plays a pivotal role in achieving longevous Zn anodes. Distinct from the previously reported carbonaceous overlayers with singular dopants and thick foreign coatings, a new type of N/O co-doped carbon skin with ultrathin feature (i.e., 20 nm thickness) is developed via the direct chemical vapor deposition growth over Zn foil. Throughout fine-tuning the growth conditions, mosaic nanocrystalline graphene can be obtained, which is proven crucial to enable the orientational deposition along Zn (002), thereby inducing a planar Zn texture. Moreover, the abundant heteroatoms help reduce the solvation energy and accelerate the reaction kinetics. As a result, dendrite growth, hydrogen evolution, and side reactions are concurrently mitigated. Symmetric cell harvests durable electrochemical cycling of 3040 h at 1.0 mA cm^-2 /1.0 mAh cm^-2 and 136 h at 30.0 mA cm^-2 /30.0 mAh cm^-2 . Assembled full battery further realizes elongated lifespans under stringent conditions of fast charging, bending operation, and low N/P ratio. This strategy opens up a new avenue for the in situ construction of conductive AIL toward pragmatic Zn anode.