We have investigated the crystallographical, morphological, and electrochemical behaviors of synthesized four different compositions of xLi2MnO3·(1−x)Li[Mn y Ni z Co1−y−z ]O2 cathode active materials using X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), and galvanostatic cycler. The four different compositions of cathode active materials demonstratea commonly angular shape of primary particles, but agglomerated spherical shape in appearance. All the attempted compositions of xLi2MnO3·(1−x)Li[Mn y Ni z Co1−y−z ]O2 cathodes deliver a specific discharge capacity of between 220 and 242mAh/g at room temperature when cycled between 2.5 and 4.6V versus Li/Li+ at C/10 rate.