Synthesis and electrochemical characteristics of layered LiNi0.6Co0.2Mn0.2O2 cathode material for lithium ion batteries

LiNi0.6Co0.2Mn0.2O2 was prepared from LiOH·H2O and Me(OH)x (Me Ni, Co, Mn) by co-precipitation and subsequent heating in air. XRD, SEM and C-V methods were used to examine the structural and electrochemical characteristics. LiNi0.6Co0.2Mn0.2O2 samples showed excellent electrochemical performances. The optimum annealing range is 800-900 °C. The reversible discharge capacity after 50 cycles of a sample heated at 900 °C is 151.6 mAh/g at RT when a cell (LiNi0.6Co0.2Mn0.2O2/Li) is cycled in 2.8-4.3 V at 0.4 C rate. Cylinder batteries (LiNi0.6Co0.2Mn0.2O2/C) were assembled. It was found that LiNi0.6Co0.2Mn0.2O2 shows excellent cycling stability at RT when cycled in 2.8-4.2 V at 0.2 C, 0.5 C, and 1 C, respectively. A C-V test showed only one couple of peaks that appeared between 3.2-4.6 V in a LiNi0.6Co0.2Mn0.2O2/Li cell, which means that a more reversible specific charge/discharge capacity is available for this material. LiNi0.6Co0.2Mn0.2O2 was tested to be a promising cathode material for lithium ion batteries.