Positive electrode materials having a superior hardness strength
A powderous positive electrode material for a lithium secondary battery has the general formula Li 1+x [Ni 1−a−b−c M a M′ b M″ c ] 1−x O 2−z . M is one or more elements of the group Mn, Zr and Ti. M′ is one or more elements of the group Al, B and Co. M″ is a dopant different from M and M′, and x, a, b and c are expressed in mol with −0.02≤x≤0.02, 0≤c≤0.05, 0.10≤(a+b)≤0.65 and 0≤z≤0.05. The material has an unconstrained cumulative volume particle size distribution value (Γ 0 (D10 P=0 )), a cumulative volume particle size distribution value after having been pressed at a pressure of 200 MPa (Γ P (D10 P=200 )) and a cumulative volume particle size distribution value after having been pressed at a pressure of 300 MPa (Γ P (D10 P=300 )). When Γ P (D10 P=200 ) is compared to Γ 0 (D10 P=0 ), the relative increase in value is less than 100%. When Γ P (D10 P=300 ) is compared to Γ 0 (D10 P=0 ), the relative increase in value is less than 120%.
1. A powderous positive electrode material for a lithium secondary battery, the material having the general formula Li 1+x [Ni 1−a−b−c M a M′ b M″ c ] 1−x O 2−z ;
M being either one or more elements of the group consisting of Mn, Zr and Ti,
M′ being either one or more elements of the group consisting of Al, B and Co,
M″ being a dopant different from M and M′,
x, a, b and c being expressed in mol with −0.02≤x≤0.02, 0≤c≤0.05, 0.10≤(a+b)≤0.65 and 0≤z≤0.05;
wherein the material has an unconstrained cumulative volume particle size distribution value (Γ 0 (D10 P=0 )), a cumulative volume particle size distribution value after having been pressed at a pressure of 200 MPa (Γ P (D10 P=200 )) and a cumulative volume particle size distribution value after having been pressed at a pressure of 300 MPa (Γ P (D10 P=300 )),
wherein when Γ P (D10 P=200 ) is compared to Γ 0 (D10 P=0 ), the relative increase in value is less than 100%,
wherein when Γ P (D10 P=300 ) is compared to Γ 0 (D10 P=0 ), the relative increase in value is less than 120%,
wherein the material has a molar amount of Ni 3+ that equals 1−2a−b, and the molar amount of Ni 3+ is greater than or equal to 0.2 and less than or equal to 0.4, and
wherein the material has a D max ≤45 μm.
2. The powderous positive electrode material of claim 1 , wherein M′=Mn and M″ is either one of Al or Co.
3. The powderous positive electrode material of claim 1 , wherein 1+x<1.
4. The powderous positive electrode material of claim 1 having a BET value≤0.37 m 2 /g.
5. The powderous positive electrode material of claim 1 having a pressed density greater than 3.0 g/cm 3 .
6. The powderous positive electrode material of claim 1 comprising up to 2 mol % of W, Mo, Nb, Zr, or a rare earth element.
7. The powderous positive electrode material of claim 1 having a soluble base content (Li 2 CO 3 +LiOH)<0.8 wt %.
8. The powderous positive electrode material of claim 1 comprising secondary particles substantially free from porosities larger than 20 nm.
9. The powderous positive electrode material of claim 1 comprising secondary particles containing less than 20 voids larger than 20 nm.
10. The powderous positive electrode material of claim 1 having a FWHM value of the (104) peak as defined by the pseudo hexagonal lattice with R-3m space group which is greater than 0.125 2-theta degrees.
11. The powderous positive electrode material of claim 1 having a FWHM value of the (015) peak as defined by the pseudo hexagonal lattice with R-3m space group which is greater than 0.125 2-theta degrees.
12. The powderous positive electrode material of claim 1 having a FWHM value of the (113) peak as defined by the pseudo hexagonal lattice with R-3m space group which is greater than 0.16 2-theta degrees.
13. The powderous positive electrode material of claim 1 having a second phase LiN x′ O y′ with 0<x′<1 and 0<y′<2, where N is either one or more of W, Mo, Nb, Zr or rare earth elements.