Positive electrode material and preparation method and use therefor, lithium-ion battery positive electrode pole piece, and lithium-ion battery

A cathode material comprising multicrystal particles (A) and single crystal particles or quasi single crystal particles (B);

• the particle diameters D5, D50 and D95 of the cathode material satisfy the relationship shown in Formula I:
• 1.5≤K95=(D95−D5)/D50≤2.5 Formula I;
• wherein the surface of the multicrystal particles (A) is coated with a cladding layer (P);
• wherein the cladding layer (P) is provided by conductive graphite and conductive polymer, or
• wherein the cladding layer (P) is provided by conductive polymer;
• wherein a mass ratio of the multicrystal particles (A) to the cladding layer (P) is 1:0.001-0.05, based on the total weight of the multicrystal particles (A);
• wherein the cathode material has a composition represented by Formula (1):
• [Li1+a(NixCoyMnzM1-x-y-z)NkO2-wJwπ (1);
• in the Formula (1), 0≤a≤0.3, 0.83≤x≤1, 0≤y≤1, 0≤z≤1, 0≤k≤0.1, 0≤w≤0.1, M is at least one selected from the group consisting of B, Na, K, Mg, Al, Ca, Ti, Fe, Zn, Sr, Y, Zr, Nb, Mo, Sn, Ba, Ta and W;
• N is at least one selected from the group consisting of B, Mg, Al, Ti, V, Sr, Y, Zr, Nb, Mo and W;
• J is at least one selected from the group consisting of F, Cl and P,
• wherein the particle diameters D5, D50 and D95 of the multicrystal particles (A) satisfy the relationship shown in Formula II:
• 0<KA95=(D95−D5)/D50<1 Formula II;
• wherein the cathode material has a powder compaction density greater than or equal to 3.63 g/cm3 under a pressure condition of 20 kN, and
• wherein content of Ni in the multicrystal particles (A) is equal with content of Ni in single crystal particles or quasi single crystal particles (B).