Uniform Zn2+ Flux Distribution Achieved by an Artificial Three-Dimensional Framework: The Enhanced Ion-Transfer Kinetics for Long-Life and Dendrite-Free Zn Anodes.

Abstract

Zinc metal has been naturally considered as the most anticipated anode material for zinc-ion batteries (ZIBs), given the benefits of large volume specific capacity, low electrode potential, and inexpensive cost. However, the growth of zinc dendrites and the corrosion of hydrogen evolution during the Zn2+ ion deposition process are the bottlenecks restricting the large-scale application of zinc metal. Herein, we report the modification of zinc anodes by utilizing a ball-milling clay precipitate (designated as BMC, consisting of the unetched MAX phase and the Ti3C2Tx phase) to construct a three-dimensional (3D) framework on the surface of zinc foil (Zn@BMC). Different from the close stacking of conventionally prepared MXene sheets after film formation, the BMC coating firmly adheres to the zinc surface through the binder. The abundant internal space relieves the stress during the volume change of the Zn metal and uniformizes the Zn2+ ion flux. Consequently, Zn@BMC not only achieves a stable long cycle (2000 h, 0.5 mA h cm-2) but also inhibits the side reaction of hydrogen evolution by physically separating the electrolyte and the zinc metal anode. We reckon that our research will aid in clarifying the design principles governing the interface of the zinc metal anode in ZIBs.