CuFe2O4 network,prepared via the electrostatic spray deposition technique,with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported.The reversible capacity can be further enhanced by coating high electronic conductive polypyrrole（PPy）.At the current density of 100mA·g-1.Li/CuFe2O4 electrode delivers a reversible capacity of 842.9 mAh·g-1 while the reversible capacity of Li/PPy-coated CuFe2O4 electrode increases up to 1106.7 mAh-g’.A high capacity of 640.7 mAhg＂1 for the Li/PPy-coated CuFe2O4electrode is maintained in contrast of 398.9 mAh·g-1 for CuFe2O4 electrode after 60 cycles,which demonstrates good electrochemical performance of the composite due to the increase of electronic conductivity.The electrochemical impedance spectroscopy（EIS） further reveals that the Li/PPy-coated CuFe2O4 electrode has a lower charge transfer resistance than the Li/CuFe2C〉4 electrode.
Graphene-wrapped Fe2O3nanorings(RGO/Fe2O3)were synthesized by a facile approach,which assembled with graphene and the Fe2O3nanorings precursor through the colloidal coagulation effect at room temperature.The uniform Fe2O3nanorings prepared by hydrothermal routes were homogeneously distributed and well wrapped by graphene.When tested as anode for lithium ion batteries,RGO/Fe2O3exhibits a high capacity and good cycling stability.This could be attributed to the interaction of ring-shaped structure and graphene sheets,which inherit the good kinetic property of Fe2O3nanorings and enhance the structural integrity with graphene sheets’support.
Urchin-like Sn–ZnO–C composite have been successfully prepared by thermal annealing of ZnSn(OH)6precursor in acetylene/argon gas(1/9;v/v).The phase of the urchin-like Sn–ZnO–C has been characterized by X-ray diffraction(XRD)and Raman spectrum.The images of scanning electron microscopy(SEM)and transmission electron microscope(TEM)demonstrate that the Sn–ZnO–C composite with an average of 3 lm in diameter is composed of many core–shell nanowires and carbon nanotubes emanated from the center.The thermal annealing temperature and time have crucial effects on the formation of urchin-like structure and carbon content of the Sn–ZnO–C composites.As an anode for lithium-ion batteries,the urchin-like Sn–ZnO–C composite delivers a discharge capacity of 1,034.5 mAh/g in initial cycle and 571.9 mAh/g reversible discharge capacity after 25 cycles at a current density of 50 mA/g.The superior energy storage properties highlight the urchin-like Sn–ZnO–C composite as a potential alternative anode material in lithium-ion batteries.
