A strategy of facile route to prepare the Li2MnO3-stabilized LiMO2 (M = Mn, Ni, Co) electrode materials, cathode materials for Lithium secondary batteries that can be operated at the high voltage greater than 4.5 V, is proposed using the method of mechanochemical process. Li2MnO3 was synthesized at 400 °C, followed by the mechanochemical process with LiMO2 to form nanocomposite with the layered–layered structure. Structures and morphologies of xLi2MnO3·(1−x)LiMO2 are investigated to confirm the layered–layered structural integration. Various mole ratios of our xLi2MnO3·(1−x)LiMO2 electrode materials exhibit a large discharge capacity about 200 mAh g−1 at the room temperature. The cycle performances and the specific discharge capacities are improved by the secondary heat treatment for the xLi2MnO3·(1−x)LiMO2 composite electrodes where x ≤ 0.5. Our experimental results suggest the mechanochemical process is an easy and effective tool to form the nanocomposite of two components with controlled composition, especially, for the layered–layered integrated structure of xLi2MnO3·(1−x)LiMO2 system.