Electrochemical Properties of Hollow, Spherical Li2O-SnO2-Cu-C Nanocomposite Powders Prepared by Spray Pyrolysis

Hollow and spherical Li2O-SnO2-Cu-C nanocomposite powder is prepared by spray pyrolysis. Examination of the nanocomposite powder shows that Li2O-SnO2-Cu particles are uniformly distributed over a hollow C matrix. Li2O-SnO2-Cu-C nanocomposite powder has better cycling performance than do Li2O-SnO2-CuO-C and Li2O-SnO2-Cu2O-C nanocomposite powders. The uniform mixing of electrochemically inactive Cu metal and electrochemically active SnO2 improves the cycling performance of Li2O-SnO2-Cu-C powder. The charge capacity of Li2O-SnO2-Cu-C nanocomposite powder drops from 547 to 449 mAh g(-1) after 130 cycles at a current density of 700 mA g(-1); the corresponding capacity retention is 82%. The capacity retention of the Li2O-SnO2-CuO-C and Li2O-SnO2-Cu2O-C nanocomposite powders after 130 cycles is 44% and 52%, respectively. The cycling performance of the SnO2-Cu-C and Li2O-SnO2-CuO nanocomposite powders is compared to that of Li2O-SnO2-Cu-C powder. The presence of Li2O and a C matrix improve the rate performance as well as the cycling performance of the nanocomposite powders by minimizing the crystal growth of SnO2 during repeated charging and discharging cycles.