Synthesis and electrochemical characteristics of xLi2MnO3·(1-x)Li(Ni1/3Co1/3Mn1/3)O2 compounds

xLi2MnO3·(1-x)Li(Ni1/3Co1/3Mn1/3)O2 (x=0.25, 0.40, 0.55) compounds were prepared by low-heating solid state reaction. In the voltage range of 2.70-4.35 V, the discharge capacity of the electrode decreased with the increase of x, with a better cyclability. However, when cycled between 2.7 and 4.6 V, the cathodes delivered much larger capacities and their capacities increased with the introduction of Li2MnO3. Moreover, it was found that the discharge capacity gradually increased with the cycle number. The reason for this phenomenon was discussed. It was found that the relatively low cut-off potential made the activation of the Li2MnO3 component in the compound a gradual process, which caused the increasing capacity.