Through a chemical lithiation method, we were able to modify the well-known anode material MoO3 to develop a new kind of a high specific energy cathode. Thus, nanobelts of MoO3 were synthetized and chemically lithiated to obtain nominally LiMoO3 (composition discovered via DFT calculations). This electrode material showed enhanced electrochemical performance (>150 mAh/g for a loading of 4 mg/cm2 at 3C rate) and can be considered as a novel cathode with high specific charge. Its reaction mechanism was explored via high resolution in situ XRD and post mortem SEM analysis, which revealed almost no damage to the nanobelts after 50 cycles.