Surface coatings of two-dimensional metal-organic framework nanosheets enable stable zinc anodes

Aqueous zinc-ion batteries (ZIBs) have been considered as safe and scalable energy storage solutions,but the dendrite and corrosion issues of Zn anodes have hindered their further application.Herein,we demonstrate that two-dimensional metalorganic framework (MOF) nanosheets can act as protective coatings to prevent dendrite formation and hydrogen evolution of Zn anodes.The morphology of MOFs was tuned from octahedral nanoparticles (UiO-67-3D) to nanosheets (UiO-67-2D),leading to significantly enhanced protective performance.UiO-67-2D nanosheets-coated Zn anodes displayed smaller polarization,longer cycling lifetime and lower H2evolution than those of UiO-67-3D nanoparticles in symmetrical cells,which has been attributed to the higher concentration of surface Zr-OH/H2O to induce uniform Zn deposition and one-dimensional (1D) channels perpendicular to the Zn surface to regulate Zn2+diffusion.The assembled UiO-67-2D@Zn||Mn2O3/C full cell shows a high capacity of240 m Ah g-1at 1 A g-1and excellent cycling stability.