Improved solid-state synthesis and electrochemical properties of LiNi0.6Mn0.2Co0.2O2 cathode materials for lithium-ion batteries

Abstract LiNi0.6Mn0.2Co0.2O2 is considered as a promising Ni-rich layered cathode material of lithium-ion batteries due to low cost and high capacity. However, it is generally prepared by complicated precursor methods. In this work, LiNi0.6Mn0.2Co0.2O2 is synthesized by a solid-state method with manganese acetate as manganese source and an effective mixing way. The as-prepared samples are characterized by XRD, FESEM, XPS and electrochemical techniques. The results show that the synthesized LiNi0.6Mn0.2Co0.2O2 cathode materials have an α-NaFeO2 type structure with insignificant cation mixing, octahedral single crystal and quasi sphere morphology, smaller particle size and good dispersion, so that it displays an initial discharge capacity of 163.6 mAh g−1 with a coulombic efficiency of 85.6% at 0.1C, a capacity retention of 99.1% after 100 cycles at 0.5C and an excellent rate performance, and also an initial discharge capacity of 177.3 mAh g−1 with capacity retention of 94.6% after 155 cycles at 55 °C.