Hydrothermal self-assembly of hierarchical flower-like ZnO nanospheres with nanosheets and their application in Li-ion batteries

In this work, hierarchical flower-like ZnO nanospheres self-assembled by nanosheets with a thickness of similar to 10 nm have been synthesized via a simple hydrothermal route together with tetramethylammonium hydroxide (TMAH) and sodium citrate. As TMAH is only used without any sodium citrate, the obtained products are ZnO nanoplates with a thickness of similar to 50 nm and a lateral size of similar to 300 nm. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and N-2-physisorption technique were employed to characterize the phase composition and microstructure of the synthesized samples. On the basis of the experimental results, a possible formation mechanism of the ZnO nanoplates and the hierarchical flower-like ZnO nanospheres has been proposed. Due to the ultrathin nanosheet and mesostructure feature, the hierarchical flower-like ZnO nanospheres as anode exhibit significant improvements in reversible capacities and cycle performance over the ZnO nanoplates. (C) 2013 Elsevier B.V. All rights reserved.