Nanosized LiCrO2·Li2MnO3 composite powders are prepared by a new concept spray pyrolysis. The precursor and post-treated powders have a Li2CrO4 impurity introduced by the partial oxidation of LiCrO2. The powders have a pure layered structure corresponding to the LiCrO2·Li2MnO3 composite after Li2CrO4 is removed by washing with distilled water. The real composition of the washed cathode powders is Li1.18Cr0.404Mn0.477O2. The aggregated post-treated powders are converted into nanosized powders after washing with distilled water; milling is not required for this conversion. The mean size of the nanosized LiCrO2·Li2MnO3 powders is 48nm. The LiCrO2·Li2MnO3 cathode sample post-treated at 750°C has initial charge and discharge capacities of 272 and 233mAhg−1 at a constant current density of 18mAg−1, respectively. The discharge capacity of the cathode sample post-treated at 750°C decreases from 233 to 222mAhg−1 by the 44th cycle, in which the capacity retention is 95%.