Positive electrode plate and lithium-ion secondary battery

1. A positive electrode plate comprising a positive electrode current collector and a positive active material layer disposed on at least one surface of the positive electrode current collector, wherein the positive active material layer comprises a first positive active material represented by Chemical Formula (1) and a second positive active material represented by Chemical Formula (2),

Li 1+x Ni a Me b M 1−a−b O 2−y A y   Chemical Formula (1),

in Chemical Formula (1), −0.1≤x≤0.2, 0<a<1, 0<b<1, 0<a+b<1, 0≤y<0.2; Me and M are each independently one or more of Co, Mn, Fe, Cr, Ti, Zn, V, Al, Zr, and Ce; Me is different with M; and A is one or more of S, N, F, Cl, Br, and I;

Li 1+z Mn c Z 2−c O 4−d B d   Chemical Formula (2)

in Chemical Formula (2), −0.1≤z≤0.2, 0<c≤2, 0≤d<1; Z is one or more of Ni, Fe, Cr, Ti, Zn, V, Al, Mg, Zr, and Ce; and B is one or more of S, N, F, Cl, Br, and I; and

wherein the positive electrode plate satisfies Formula (1),

0.04≤ R·P/C≤ 10  Formula (1)

in Formula (1), R is the resistance of the positive electrode plate, and the unit of R is Ω; P is the packing density of the positive electrode plate, and the unit of P is g/cm 3 ; C is the single-side areal density of the positive electrode plate, the unit of C is g/1540.25 mm 2 .

2. The positive electrode plate according to claim 1 , wherein the positive electrode plate satisfies Formula (2),

0.5≤ R·P/C≤ 8  Formula (2).

3. The positive electrode plate according to claim 1 , wherein the resistance R of the positive electrode plate is less than 5Ω.

4. The positive electrode plate according to claim 1 , wherein the packing density P of the positive electrode plate is from 2.6 g/cm 3 to 3.5 g/cm 3 .

5. The positive electrode plate according to claim 1 , wherein the single-side areal density C of the positive electrode plate is from 0.25 g/1540.25 mm 2 to 0.40 g/1540.25 mm 2 .

6. The positive electrode plate according to claim 1 , wherein a weight ratio of the first positive active material and the second positive active material is 0.05:1 to 19:1.

7. The positive electrode plate according to claim 1 , wherein the second positive electrode active material is present in an amount of 4 wt % to 95 wt % in the positive active material layer.

8. The positive electrode plate according to claim 1 , wherein:

the first positive active material has an average particle diameter Dv50 of 4 μm to 18 μm, and has an average particle diameter Dv90 of 10 μm to 24 μm; and/or,

the second positive active material has an average particle diameter Dv50 of 8 μm to 20 μm, and has an average particle diameter Dv90 of 14 μm to 35 μm.

9. The positive electrode plate according to claim 1 , wherein in Chemical Formula (1), 0.5≤a<1, Me and M are each independently one or more of Co, Mn, and Al.

10. A lithium-ion secondary battery comprising a positive electrode plate according to claim 1 , a negative electrode plate, a separator, and an electrolyte.

11. The positive electrode plate according to claim 1 , wherein the resistance R of the positive electrode plate is 1Ω or less.

12. The positive electrode plate according to claim 1 , wherein a weight ratio of the first positive active material and the second positive active material is 0.4:1 to 19:1.

13. The positive electrode plate according to claim 1 , wherein the second positive electrode active material is present in an amount of 4 wt % to 67 wt % in the positive active material layer.

14. The positive electrode plate according to claim 8 , wherein:

the first positive active material has an average particle diameter Dv50 of 8 μm to 16 μm, and has an average particle diameter Dv90 of 10 μm to 20 μm.

15. The positive electrode plate according to claim 8 , wherein:

the second positive active material has an average particle diameter Dv50 of 11 μm to 16 μm, and has an average particle diameter Dv90 of 18 μm to 30 μm.