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.