ZnAl-layered double hydroxide nanosheets-coated ZnO@C microspheres with improved cycling performance as advanced anode materials for zinc-based rechargeable batteries

High-performance Zn-Al layered double hydroxide nanosheets-coated spherical ZnO@C composite is successfully fabricated for use as advanced anode materials of zinc-based rechargeable batteries. It is interestingly found that the spherical ZnO@C-ZnAl layered double hydroxide (15%) composite with a proper coated content of ZnAl layered double hydroxide shows a superior cycling performance, satisfactory volume specific capacity and enhanced high-rate properties. After 400 cycles at 1C/1C and 200 cycles at 1C/5C, the ZnO@C-ZnAl layered double hydroxide (15%) exhibits enhanced capacity retention of 81.6%. In contrast, the pristine ZnO shows low capacity retention of only 46.3% after 200 cycles at 1C/1C. These performance improvements can be mainly attributable to the synergistic effect of the surface coating with Zn-Al layered double hydroxide and in-situ doping with carbon. The coated Zn-Al layered double hydroxide nanosheets can modify the“dissolution-deposition” process of ZnO anode and the doped C can enhance its electronic conductivity, eventually leading to the reduced electrochemical resistance, improved reaction reversibility, and enhanced structural stability. As a result, it is believed that the spherical ZnO@C-ZnAl layered double hydroxide (15%) composite is a promising advanced anode material for zinc-based rechargeable batteries.