Electrochemical properties of LiNi1−yTiyO2 and LiNi0.975M0.025O2 (M = Zn, Al, and Ti) synthesized by the solid-state reaction method

LiNi1−yTiyO2 (y = 0.000, 0.012, 0.025, 0.050, 0.100, and 0.150) and LiNi0.975M0.025O2 (M = Zn, Al, and Ti) were synthesized by the solid-state reaction method. The voltage vs. discharge capacity curves for y = 0.012 and y = 0.025 exhibit four distinct plateaus corresponding to phase transitions. Among LiNi1−yTiyO2, LiNi0.975Ti0.025O2 has the largest first discharge capacity, 154.8 mAh/g, at a rate of 0.1 C, and a relatively good cycling performance (77% at n = 10). Among LiNi0.975M0.025O2 (M = Zn, Al, and Ti) samples, the LiNi0.975Ti0.025O2 sample had the largest first discharge capacity. The LiNi0.975Ti0.025O2 sample has sharper peaks for the −dx/|dV| vs. V curves than the LiNi0.975M0.025O2 (M = Zn and Al). The LiNi0.975Al0.025O2 sample, with the first discharge capacity of 128.5 mAh/g at a rate of 0.1 C, has the best cycling performance (98% at n = 10).