Pulverulent compounds, a process for the preparation thereof and the use thereof in lithium secondary batteries
View Patent ↗The present invention relates to pulverulent compounds of the formula Li a Ni b M1 c M2 d (O) 2 (SO 4 ) x , a process for preparation thereof and the use thereof as active electrode material in.
1. A pulverulent compound of the formula Li a Ni b M1 c M2 d (O) 2 (SO 4 ) x , in which M1 denotes at least one element selected from the group consisting of Fe, Co, Cr, Mg, Zn, Cu and/or mixtures thereof, M2 denotes at least one element selected from the group consisting of Mn, Al, B, Ca, Sr, Ba, Si and/or mixtures thereof, and 0.95≦a≦1.1, 0.3≦b≦0.83, 0.1≦c≦0.5, 0.03≦d≦0.5 and 0.001≦x≦0.03, wherein secondary particles composed of a multiplicity of primary particles of the pulverulent compound have a compressive strength of at least 100 MPa and the secondary particles have a normalized width of the particle size distribution, measured according to the Formula (1)
D
90
-
D
10
D
50
(
1
)
in which D denotes the diameter of the secondary particles, is not more than 0.89;
wherein the pulverulent compound is prepared by thoroughly mixing a co-precipitated nickel-containing precursor with a lithium-containing component to form a homogeneous mixture, and heating the mixture in a plurality of temperature stages.
2. The pulverulent compound according to claim 1 , wherein the secondary articles have a compressive strength of at least 200 MPa.
3. The pulverulent compound according to claim 1 , wherein the secondary particles have a compressive strength of at least 300 MPa.
4. The pulverulent compound according to claim 1 , wherein the secondary particles have a porosity of up to 0.01 cm 3 /g measured according to ASTM D 4222.
5. The pulverulent compound according to claim 1 , wherein the secondary particles have a porosity of up to 0.008 cm 3 /g measured according to ASTM D 4222.
6. The pulverulent compound according to claim 1 , wherein the secondary particles have a porosity of up to 0.006 cm 3 /g measured according to ASTM D 4222.
7. The pulverulent compound according to claim 1 , wherein the secondary particles have a spheroidal shape.
8. The pulverulent compound according to claim 7 , wherein the secondary particles have a shape factor greater than 0.8.
9. The pulverulent compound according to claim 7 , wherein the secondary particles have a shape factor greater than 0.9.
10. The pulverulent compound according to claim 1 , wherein the secondary particles have a D10 value, measured according to ASTM B 822, after compression of the material at a pressure of 200 MPa changes by not more than 0.5 μm compared with the starting material.
11. The pulverulent compound according to claim 1 , wherein the secondary particles have a D90 value, measured according to ASTM B 822, after compression of the material at a pressure of 200 MPa changes by not more than 1 μm compared with the starting material.
12. The pulverulent compound according to claim 1 , wherein the secondary particles have a compressed density of at least 3.2 g/cm 3 at a compression pressure of 200 MPa.
13. The pulverulent compound according to claim 1 , wherein the secondary particles have a tapped density measured according to ASTM B 527, of at least 2.2 g/cm 3 .
14. The pulverulent compound according to claim 1 , wherein the secondary particles have a tapped density measured according to ASTM B 527, of at least 2.4 g/cm 3 .