Agglomeration-like multi-element cathode material, preparation method therefor, and lithium-ion battery

A lithium-ion battery, comprising an agglomeration-like multi-element cathode material, the agglomeration-like multi-element cathode material having a structure represented by formula I:

• LiaNixCoyMnzMbO2 formula I;
• where:
• 0.9≤a≤1.1, 0.5≤x<1, 0<y<0.5, 0<z<0.5, and 0≤b<0.05;
• and M is at least one of V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, Sr, and Ti,
• wherein the multi-element cathode material is secondary particles formed by agglomeration of primary particles, the primary particles having a spherical shape and having an average particle size DS ranging from 1.2 μm to 1.8 μm, the secondary particles having an average particle size DL ranging from 7 μm to 13 μm, and a value of DL/DS ranging from 7 to 12, the average particle size DL being measure by means of scanning electron microscope;
• wherein grain boundaries of the primary particles and surfaces of the secondary particles are rich in Co;
• and wherein:
• a molar percentage of Co at centers of the primary particles is defined as K1, a molar percentage of Co at the grain boundaries of the primary particles is defined as K2, and a molar percentage of Co on the surfaces of the secondary particles is defined as K3, where:
• K2−K1≥0.5%, and K3−K1≥1.5%;
• and
• wherein a value of a full width at half maximum (FWHM)(104) of a characteristic peak (104) of an X-ray diffraction(XRD) test of the agglomeration-like multi-element cathode material ranges from 0.202 to 0.23.