POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION BATTERY, POSITIVE ELECTRODE FOR RECHARGEABLE BATTERY, AND LITHIUM ION BATTERY

摘要

Provided is a positive electrode active material for a lithium ion battery positive electrode material made of lithium-containing nickel-manganese-cobalt composite oxide of a layered structure represented with LiaNixMnyCozO 2 (1.0 < a < 1.3, 0.8 < x + y + z < 1.1), wherein, in a region with a molar volume Vm that is estimated from a lattice constant calculated from a (018) plane and a (113) plane in a powder X-ray diffraction pattern using CuK alpha rays as a vertical axis and Co ratio z (molar %) in metal components as a horizontal axis, the relationship thereof is within a range of Vm = 21.276 - 0.0117z as an upper limit and Vm = 21.164 - 0.0122z as a lower limit, and a half value width of both the (018) plane and the (113) plane is 0.200° or less. As a result of studying and defining the relationship of the cobalt (Co) ratio and the lattice constant, which are considered to influence the crystal structure, obtained was a positive electrode active material having high crystallinity, high capacity and high security. By using this material, it is possible to obtain a positive electrode active material for a lithium ion battery that is able to further ensure the characteristics and safety of the lithium ion battery.