First-principles calculations are used to analyze the phase stability, formation energy, and Li intercalation potential for a series of layered cathode materials. The calculations show LiNi0.66Co0.17Mn0.17O2 as a promising cathode for lithium-ion batteries. The layer-structured LiNi0.66Co0.17Mn0.17O2 is prepared via wet chemical route, followed by annealing at 1123K and characterized using powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The characterization techniques reveal single-phase LiNi0.66Co0.17Mn0.17O2 with highly ordered structure. Galvanostatic charge–discharge curves recorded at 1C show the discharge capacity of ca. 167mAhg−1 and good cyclic performance for 25 cycles.