Porous ZnO nanosheets grown on copper substrates as anodes for lithium ion batteries

Porous ZnO nanosheets are grown directly on copper substrates by a chemical bath deposition technique followed by a heat treatment. The materials are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Their electrochemical properties as anodes of lithium ion batteries are examined by cyclic voltammetry (CV) and galvanostatic discharge-charge tests. The results show that porous ZnO nanosheets exhibit higher reversible capacities and better cyclabilities than those of commercial ZnO powders. When cycled at 0.05 A g(-1), these nanosheets deliver initial discharge and charge capacities of 1120 and 750 mAh g(-1), and at 0.5 A g(-1), they keeps stable capacities of 400 mAh g(-1) up to 100 cycles, in addition, they also exhibit good rate capabilities. It is believed that the porous sheet nanostructure plays an important role in the electrochemical performance. (C) 2011 Elsevier Ltd. All rights reserved.