Synthesis and properties of LiGaxMgyN1-x-yO2 as cathode material for lithium ion batteries

Simultaneous doping of magnesium (Mg) and gallium (Ga) at the Ni-site in LiNiO2 has been tried to improve the cathode performance, in view of the recent reports that Ga or Mg dopants can suppress the crystallographic phase transitions and decrease the irreversible capacity. The results show that co-doping (2 atom% Ga and 3 atom% Mg) definitely has a large beneficial effect in increasing the capacity (150 mAh/g) and cycling behavior. Comparison of the differential capacity vs. voltage curves for pristine and co-doped LiNiO2, show suppression of the phase transitions and stabilization of the hexagonal (H1) phase. Differential scanning colorimetry (DSC) data indeed confirm the above by way of increased thermal stability of the charged cathode. (C) 2000 Elsevier Science B.V. All rights reserved.