The structure of a 3 V LixMnO cathode and its change upon electrochemical lithiation

The crystal structure of Li0.33MnO2 obtained by heat-treatment of a gamma-MnO2 and LiNO3 mixture (Li/Mn ratio 1:3, 370 degrees C, 20 h), which is used as a 3 V cathode in rechargeable lithium batteries, is proposed as an ordered alternation of [1 x 2] and [1 x 1] channels. The simulation of this structure by the Rietveld method is in good agreement with the powder X-ray diffraction pattern of this material. It has been shown that the major difference between the structures of gamma-MnO2 and the thermal lithiated product is the ordering in the MnO6-octahedra arrangement. This leads to the high reversibility and cyclability of this cathode material in rechargeable Li batteries.