Electrochemical Properties of Nanosized Li₂MnO₃-Li(Ni_1/3Co_1/3Mn_1/3)O₂ Composite Cathode Powders Prepared by Spray Pyrolysis

摘要

Nanosized 0.6Li2MnO3.4Li(Ni1/3Mn1/3Co1/3)O2 composite powders are prepared by spray pyrolysisat high post-treatment temperatures. The optimum concentrations of citric acid and ethylene glycol,selected as the appropriate organic additives to obtain the composite nanopowders, are 0.2 M each. Thespherical precursor powders of large size, with hollow and porous structures, are converted intocomposite nanopowders. Transmission electron microscopy, X-ray diffraction, X-ray photoelectronspectroscopy, and the cycling properties of the powders indicate that the optimum post-treatmenttemperature for obtaining composite cathode nanopowders is 900 C. The mean size of the compositepowders post-treated at 900 C is 136 nm. The composite cathode powders post-treated at 900 C have-1 high initial charge/discharge capacities of 350 and 291 mAh g . The discharge capacity of the composite cathode powder post-treated at 900 C decreases from 291 to 269 mAh g by the 30th cycle,in which the capacity retention is 92.4%.