Synthesis, XRD characterization, and cycling performance of cobalt doped lithium nickelates

A simple method for the synthesis of LiNi1−yCoyO2 with y=0.2–0.3 is developed based on the solid state reaction between LiOH and a mixed oxide precursor, Ni1−yCoyO2, with a high dispersity and a homogeneous distribution of Ni and Co. The precursor is obtained by ordinary processes, comprising dissolution, evaporation drying and thermal decomposition, avoiding the recently reported sophisticated operations and complex equipment, which makes it viable for industrial application. The reproducible good values of the XRD criterial parameters image and Vh lend evidence for a high stoichiometry and low cation disorder of the samples. The VA-grams of the samples with y above 0.15 reveal that the numerous phase transitions of the LiNiO2 base are reduced to only one, whereby the cycling stability of the cathode material is considerably enhanced. The discharged capacity of the cathodes with y from 0.2 to 0.30 and with a loading from 15 to 21 mg/cm2 cycled at the C/2 rate (1.2–1.7 mA/cm2) between 4.30 and 2.80 V varies from 190 to 176 mAh/g at the 10th cycle and reaches 160–165 mAh/g at the 60th cycle.