A series of Ni0.6CoxMn0.4-x(OH)(2) hydroxide precursors with x=0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 are prepared by co-precipitation method from sulfate solutions using NaOH and NH4OH as precipitation and complexing agents. Then, well-ordered layered LiNi0.6CoxMn0.4-xO2 are synthesized by sintering the mixture of as-prepared precursors and LiOH center dot H2O at 820 degrees C for 12 h in flowing oxygen. Their structural and electrochemical properties are investigated using X-ray diffraction(XRD), scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS), charge-discharge test, Cyclic voltammetry (C-V) and electrochemical impedance spectroscopy (EIS). The increase of the Co content in LiNi0.6CoxMn0.4 O-x(2) leads to the decrease of the tap-density of the powders, the increase of discharge capacity and the deterioration of cycling performance. It also leads to the enhancement of the ratio Ni-3 (+)/Ni2+ in LiNi0.6CoxMn0.4 O-x(2), confirmed by the XPS analysis. The results show that the sample with x=0.2 has the highest tap-density, delivers an initial discharge capacity of 172.3 mAh g(-1) at 1C rate between 2.8 and 4.3V, more than 94.1% of that is retained after 100 cycles, and also with excellent rate capability and high-temperature performance. (C) 2014 Elsevier Ltd. All rights reserved.