Positive electrode material for lithium ion battery and preparation method therefor, positive electrode piece, and secondary battery

A method for preparing a positive electrode material for a lithium ion battery, comprising:

• mixing a lithium source and a transition metal element source to obtain a first raw material;
• performing first sintering on the first raw material in an oxygen-containing atmosphere to obtain a precursor material;
• and
• dispersing the precursor material in an amorphous conductive material, mixing the precursor material and the amorphous conductive material, and performing second sintering to obtain the positive electrode material.

A positive electrode piece having a positive electrode material for the lithium ion battery, the positive electrode material comprising:

• an inner core having a first transition metal oxide having (003) crystal planes;
• a first shell layer covering a surface of the inner core, the first shell layer comprising a second transition metal oxide;
• and
• a second shell layer covering a surface of the first shell layer away from the inner core;
• wherein at least one of a space group and a material is different between the first transition metal oxide and the second transition metal oxide,
• an angle between a plane where at least part of the (003) crystal planes in the inner core are located and a first interface being about 80° to about 100°, where the first interface is defined as a surface of the second shell layer away from the first shell layer, and
• a material of the second shell layer includes an amorphous conductive material.