Lithium manganese oxide–conductive carbon nanocomposite cathodes for rechargeable lithium batteries

A nanostructured lithium manganese oxide (LixMnOz) synthesized by reducing lithium permanganate with methanol in presence of lithium hydroxide has been mixed with conductive carbon in two different ways: ball milling and mixing in a mortar and pestle. The manganese oxide–conductive carbon composite cathodes thus obtained are characterized by electrochemical discharge–charge, density, and Brunauer–Emmett–Teller (BET) surface area measurements as well as by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The ball-milled composites exhibit superior performance in terms of discharge capacity (>200 mAh/g), cyclability, and charge efficiency in lithium cells compared to the composites obtained by mixing in a mortar and pestle. The composites obtained by ball milling are found to have higher density and smaller surface area with an intimate mixing of the manganese oxide and carbon on a nanometer scale to give a nanocomposite.