Electrochemical properties of LiNiO 2 and LiNiO 2 substituted with Ga, Al and/or Ti

Abstract

The LiNi 1− y M y O 2 specimens with compositions LiNiO 2, LiNi 0.975Ga 0.025O 2, LiNi 0.975Al 0.025O 2, LiNi 0.995Ti 0.005O 2, and LiNi 0.990Al 0.005Ti 0.005O 2 were synthesized by wet milling and solid-state reaction method. All the synthesized samples possessed the α-NaFeO 2 structure of the rhombohedral system (space group; R 3 ¯ m ) with no evidence of any impurities. Among all the specimens, LiNi 0.990Al 0.005Ti 0.005O 2 has the largest first discharge capacity, 196.3 mAh/g, at a rate of 0.1 C. At n = 50 LiNiO 2 has the largest discharge capacity, 126.7 mAh/g. LiNiO 2 has the best cycling performance, its degradation rate of discharge capacity being 0.73 mAh/g/cycle.