Electrochemical study of Si doped LiNi/sub x/Mn/sub y/Co/sub (1-x-y)/O/sub 2/ as cathode material for Li-ion secondary battery

A new synthetic route of Li[NiMnCo]O/sub 2/ was contrived and its electrochemical characteristics were enhanced by doping small amount of Si. The newly synthesized Li[NiMnCo]O/sub 2/ showed the capacity of 175 mAh/g and good cycle life at as high cut-off voltage as 4.5V. Si-doped material showed improved rate capability, specific capacity, and cycle life. It seems that the increased lattice parameters and lowered electrochemical impedance are the main causes for the improvement.