LITHIUM ION BATTERY POSITIVE ELECTRODE MATERIAL AND PREPARATION METHOD THEREFOR

A lithium-ion battery cathode material and a method for preparing the same are disclosed. The lithium-ion battery cathode material includes a layered cathode material matrix and a defect layer. The layered cathode material matrix includes body layers and lithium layers, and the body layer includes a transition metal layer and a lithium layer. The defect layer includes atoms with a periodic arrangement different from that of atoms in the matrix or with content different from that of an element in the matrix. The defect layer is parallel to a 003 crystal plane of the layered cathode material matrix, and dimensions of the defect layer are 0.1 nm to 50 nm in at least one direction and 10 nm to 5000 nm in at least another direction. When the defect layer includes atoms with the periodic arrangement from that of the atoms in the matrix, an interlayer spacing of the defect layer is different from an interlayer spacing of the matrix. When the defect layer includes atoms with content different from that of the element in the matrix, the defect layer includes a first element or a second element, and content of the first element or the second element in the defect layer is greater than or equal to that in the layered cathode material matrix. The first element or the second element in the defect layer fills a gap between the body layers, or ions formed by the first element in the defect layer replace cations in the layered cathode material matrix, or ions formed by the second element in the defect layer replace anions in the layered cathode material matrix. During a charge/discharge process, the defect layer in the lithium-ion battery cathode material plays a role in buffering a volume change of the cathode material, so as to stabilize a structure of the lithium-ion battery cathode material.