Nanosheets-based ZnO–NiO microspheres for lithium-ion batteries

Nanosheets-based ZnO–NiO microspheres were synthesized by a simple hydrothermal route combined with subsequent heat treatment at moderate temperature. The physical properties of the resulting samples were characterized by scanning electron microscopy, transmission electron microscope, and X-ray diffraction, respectively. The results show that composite materials, nanosheets-based ZnO–NiO microspheres have been successfully synthesized. For comparison, nanosheets-based ZnO or NiO microspheres were also prepared in the similar method. The nanosheets-based ZnO–NiO microspheres obtained after annealing at 500 °C showed a remarkable composite effect, delivering a higher discharge capacity (733 mAh g⁻¹ at 100 mA g⁻¹ after 50 cycles) and excellent cycling stability in comparison to those of single ZnO or NiO nanosheets. These findings make ZnO–NiO microspheres promising anodes for lithium-ion batteries. The results of this study also offer possibilities of improving the lithium storage capacity of transition metal oxides by controlling both architecture and composition.