POSITIVE ELECTRODE ACTIVE SUBSTANCE FOR NONAQUEOUS ELECTROLYTE SECONDARY CELL, METHOD FOR PRODUCING SAME, AND NONAQUEOUS ELECTROLYTE SECONDARY CELL USING POSITIVE ELECTRODE ACTIVE SUBSTANCE

摘要

A positive electrode active material is provided that has a high capacity, a low irreversible capacity, an excellent initial charge/discharge efficiency, and excellent rate characteristics. This positive electrode active material comprises a hexagonal lithium nickel complex oxide having a layer structure and represented by the general formula LixNi1-y-zCoyMzO2 (0.98≦x≦1.04, 0.25≦y≦0.40, 0≦z≦0.07, and M is at least one element selected from Al, Ti, Mn, Ga, Mg, and Nb), wherein a lithium occupancy rate in a lithium main layer as obtained by Rietveld analysis from the x-ray diffraction pattern is at least 98.7%, and a crystallite diameter as calculated from the peak for the (003) plane in x-ray diffraction is 50 to 300 nm.

主权项

1. A positive electrode active material for a nonaqueous electrolyte secondary battery,
the material comprising a hexagonal lithium nickel complex oxide having a layer structure and represented by the general formula LixNi1-y-zCoyMzO2 (0.98≦x≦1.04, 0.25≦y≦0.40, 0≦z≦0.07, and M is at least one element selected from Al, Ti, Mn, Ga, Mg, and Nb), wherein a lithium occupancy rate in a lithium main layer as obtained by Rietveld analysis from the x-ray diffraction pattern is at least 98.7%, and a crystallite diameter as calculated from the peak for the (003) plane in x-ray diffraction is 50 to 300 nm.