Comparative study of the electrochemical performance of LiNi^sub 0.5^Co^sub 0.2^Mn^sub 0.3^O^sub 2^ and LiNi^sub 0.8^Co^sub 0.1^Mn^sub 0.1^O^sub 2^ cathode materials for lithium ion batteries

LiNi0.5Co0.2Mn0.3O2 (NCM 523) and LiNi0.8Co0.1Mn0.1O2 (NCM 811) cathode materials were synthesized via a solid state reaction routine. XRD investigation revealed a hexagonal layered structure without impurity phase for the two samples and significant increase in the diffraction intensity ratio of I (003)/I (104) were observed. SEM showed no obvious secondary particles size change, but the tiny primary particles of the NCM 811 sample were smaller than those of the NCM 523 sample. The electrochemical tests exhibited the different electrochemical behaviors for the two samples. The calculation of diffusion coefficients showed that the DLi+ values of the NCM 523 and NCM 811 electrodes were calculated to be 1.14 × 10−9 and 3.04 × 10−9 cm2/s, respectively, which indicated that Li-ion diffused faster in the NCM 811 electrode.