Abstract:A series of layered LiNi_0.8-xCo_0.1Mn_0.1La_xO₂ (x=0, 0.01, 0.03) cathode materials were synthesized by combining co-precipitation and high temperature solid state reaction to investigate the effect of La-doping on LiNi_0.8Co_0.1Mn_0.1O₂. A new phase La₂Li_0.5Co_0.5O₄ was observed by XRD, and the content of the new phase could be determined by Retiveld refinement and calculation. The cycle stability of the material is obviously increased from 74.3% to 95.2% after La-doping, while the initial capacity exhibits a decline trend from 202 mA·h/g to 192 mA·h/g. The enhanced cycle stability comes from both of the decrease of impurity and the protection of newly formed La₂Li_0.5Co_0.5O₄, which prevents the electrolytic corrosion to the active material. The CV measurement confirms that La-doped material exhibits better reversibility compared with the pristine material.

Key words: nickel-rich cathode material; La-doping; electrochemical property; cycle stability; Li-ion diffusion coefficient