Study on the Co_3O_4 negative materials for lithium-ion batteries

The Co3O4 negative materials were obtained by adding metal powder such as Fe,Ni or Mn to Co3O4 using mechanical milling.As a result,Co3O4 showed a low initial coulombic efficiency,66%,and poor cycle performance when it was used as negative material by itself.The Fe powder had no effect when added to Co3O4.When adding the powder of Ni,it showed improvement in initial coulombic efficiency.But the reversible capacity faded fast after 10 cycles.When adding the powder of Mn,it showed a high initial coulombic efficiency,77%,and excellent cycle performance,713 mAh/g after 20 cycles.The coulombic efficiency was above 97%.The reaction mechanism of cobalt oxide with lithium was discussed after adding Ni or Mn powders.