Li[Cr0.290Li0.240Mn0.470]O-2 with nanocomposite structures was synthesized by a solution method with subsequent quenching. The crystalline structure was investigated by X-ray diffraction (Rietveld refinement), electron diffraction, and HRTEM. According to coindexed electron diffraction patterns and HRTEM images, Li[Cr0.290Li0.240Mn0.470]O-2 was found to be nanocomposite powders indexed in monoclinic and hexagonal structures. The nanocomposite cathode prevented spinel-like structural transformation during cycling and delivered a good reversible capacity of about 195 mA h/g.