Facile growth of ZnO nanosheets standing on Ni foam as binder-free anodes for lithium ion batteries.

ZnO has attracted increasing attention as an anode for lithium ion batteries. However, the application of such anode materials remains restricted by their poor conductivity and large volume changes during the charge/discharge process. Herein, we report a simple hydrothermal method to synthesize ZnO nanosheets with a large surface area standing on a Ni foam framework, which is applied as a binder-free anode for lithium ion batteries. ZnO nanosheets were grown on Ni foam, resulting in enhanced conductivity and enough space to buffer the volume changes of the battery. The ZnO nanosheets@Ni foam anode showed a high specific capacity (1507 mA h g at 0.2 A g), good capacity retention (1292 mA h g after 45 cycles), and superior rate capacity, which are better than those of ZnO nanomaterial-based anodes reported previously. Moreover, other transition metal oxides, such as FeO and NiO were also formed on Ni foam with perfect standing nanosheets structures by this hydrothermal method, confirming the universality and efficiency of this synthetic route.