A New Scalable Preparation of Metal Nanosheets: Potential Applications for Aqueous Zn‐Ion Batteries Anode

Abstract 2D metal nanosheets are attractive for various applications stemming from the intriguing characteristics related with their dimensionality; however, their effective and scalable preparation remains a great challenge. Herein, a scalable preparation process of relatively active metal nanosheets (e.g., Zn, Al, and Cu) with the thickness down to several nanometers at low cost is demonstrated, which involves an initial self‐folding‐rolling step followed by the subsequent ultrasonication to exfoliate them without any etching step. The native oxide on the surface of the metals, which acts as a barrier between the adjacent metal layers, plays a special role in enabling the successful preparation of 2D metal nanosheets. As a demonstration for their practicability, a hierarchical Zn anode, which is constructed by the Zn microsheets coated with carbon (Zn MS@C) via in situ carbonization of carboxymethylcellulose (CMC) binder, is successfully implemented as anode for rechargeable aqueous Zn‐ion batteries. When applied in symmetrical battery, the Zn MS@C delivers a long lifespan of over 800 h at 0.2 mA cm −2 with a capacity of 0.1 mA h cm −2 . Importantly, the full battery of MnO 2 || Zn MS@C also performs a high discharge capacity of 217.4 mA h g −1 after 140 cycles at 300 mA g −1 .