Synthesis and characterization of LiNi0.85Co0.15−2x(TiMg)xO2 as cathode materials for lithium-ion batteries

Samples of LiNi0.85Co0.15−2x(TiMg)xO2 (x = 0.0125, 0.025 and 0.05), prepared by solid state reaction at 725 °C for 24 h from LiOH·H2O, Ni2O3, Co2O3, TiO2 and Mg(OH)2 under oxygen flow, were characterized by TG–DTA, XRD and electrochemical tests. LiNiO2 simultaneously doped by Co-Ti-Mg has been tried to improve the cathode performance. The results show that co-doping (x = 0.025) definitely has a large beneficial effect in increasing the capacity (182.7 mA h g−1 of the first discharge capacity for LiNi0.85Co0.10(TiMg)0.025O2) and cycling behavior (170.6 mA h g−1 after 15 cycles). Differential capacity versus voltage curves indicate the co-doped LiNiO2 show suppression of the phase transitions as compared with LiNiO2.