Variations in the electrochemical properties of metallic elements-substituted LiNiO2 cathodes with preparation and cathode fabrication conditions

Variations in the electrochemical properties of LiNiO2 with preparation and cathode fabrication conditions were studied. The LiNiO2 cathode fabricated with a weight ratio of LiNiO2: acetylene black: binder = 85:10:5, after wet Spex milling for 60 min and drying in a shaking incubator showed the best cycling performance, with a discharge capacity degradation rate of 1.06 mAh/g/cycle between the first cycle and the 20th cycle and a discharge capacity at n = 20 of 143.5 mAh/g at 0.1 C rate. LiNi1−y M y O2 cathodes with active material compositions of LiNiO2, LiNi0.975Ga0.025O2, LiNi0.975Al0.025O2, LiNi0.995Ti0.005O2, and LiNi0.990Al0.005Ti0.005O2 were fabricated under these conditions. Among all the samples, LiNi0.990Al0.005Ti0.005O2 had the highest first discharge capacities at 0.1 C rate (196.3 mAh/g) and 0.5 C rate (147.3 mAh/g). This sample had the smallest R-factor value, indicating that it had the lowest degree of cation mixing. At 0.1 C rate LiNiO2 had the best cycling performance. At 0.5 C rate LiNi0.975Al0.025O2 had the best cycling performance and its discharge capacity degradation rate was 1.28 mAh/g/cycle between the first cycle and the 20th cycle.