Electrochemical performances of layered LiNi0.7CO0.3–xMxO2 (M=Al, Mn, Cr; x=0.05) cathode materials for rechargeable lithium batteries Original Research Article

The effects of dopants on the microstructure and electrochemical properties of layered LiNi0.7Co0.3−xMxO2 (M=Al, Mn, Cr; x=0.05) were investigated. X-ray diffraction data showed that all the phase structures were identified as a single hexagonal lattice of the α-NaFeO2 type. X-ray photoelectron spectroscopy results suggested that the oxidation states of Mn and Cr were Mn4+ and Cr6+, respectively. The constant current charge–discharge experiments showed that the cycle stability was improved at the expense of reversible capacity when Al was added. Cr doping deteriorated the cycle performances. Both reversible capacity and cycle stability were increased by Mn doping. In view of electrochemical performances, Mn doping was superior to those of LiNi0.7Co0.3O2-based cathode materials.