ELECTROCHEMICAL PERFORMANCES OF COMPOSITE CATHODE MATERIALS Li1.2Ni0.17Co0.10Mn0.53O2 and Li1.2Ni0.2Mn0.6O2

The structural, morphological and electrochemical characteristics of the composite cathode materials Li1.2Ni0.17Cо0.10Mn0.53O2 and Li1.2Mn0.6Ni0.2O2 have been investigated. Solution combustion synthesis has been used as the synthesis method. After heat treatment the average size of particle aggregates in both cathode materials was 5.9-6.5 μm. X-ray diffraction analysis shows that Li1.2Ni0.17Cо0.10Mn0.53O2 and Li1.2Mn0.6Ni0.2O2 consist of a mixture of primary substitutional solid solutions based on phases with an α-NaFeO2 and Li2MnO3 or an α-NaFeO2, Li2MnO3 and LiMn2O4 structure. The discharge specific characteristics of these materials are characterized by values of 230-250 mAh g−1. By using electrochemical impedance it was determined that the charge transfer resistance in the investigated materials is by an order of magnitude higher than that in the monophase layered materials of an α-NaFeO2 type. The following kinetic parameters were determined: the diffusion coefficient Li+, the energy barrier at Li+ migration through the solid electrolyte interphase, and the activation energy of the intercalation/deintercalation reaction.