Glass-coated cathode powders for rechargeable batteries

Patent metadata

Field	Value
Publication number	US-10020495-B2
Application number	US-201214009165-A
Country	US
Kind code	B2
Filing date	Mar 20, 2012
Priority date	Apr 6, 2011
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

The invention provides a cathode active material for use in a rechargeable battery, comprising a coated lithium nickel oxide powder or a coated lithium nickel manganese oxide powder, the powder being composed of primary particles provided with a glassy lithium silicate surface coating. A method for preparing the cathode active material comprises the steps of:
providing a lithium transition metal based oxide powder, providing an alkali mineral compound comprising a Li 2−x SiO 3−0.5x compound, wherein 0<x<2, mixing the lithium transition metal based oxide powder and the alkali mineral compound to form a powder-mineral compound mixture, and heat treating the mixture at a temperature T whereby lithium is extracted from the surface of the metal based oxide powder to react with the alkali mineral compound, and a glassy surface coating is formed comprising a Li 2−x″ SiO 3−0.5x″ compound, wherein x<x″<2.

First claim

The invention claimed is:

1. A cathode active material for use in a rechargeable battery, comprising a coated lithium nickel oxide powder or a coated lithium nickel manganese oxide powder, the powder comprising primary particles having a glassy surface coating, wherein the coating comprises a lithium silicate compound, wherein the lithium silicate compound has lithium accepting properties, and wherein the coating comprises a compound having a chemical composition expressed by Li 2−x SiO 3−0.5x , wherein 0<x≤1.6.

2. The cathode active material of claim 1 , wherein the glassy surface coating further comprises either one or both of a phosphate and borate compound, said compound having lithium accepting properties.

3. The cathode active material of claim 1 , wherein the glassy surface coating comprises lithium.

4. The cathode active material of claim 2 , wherein the glassy surface coating comprises either one or both of a Li 3−2y PO 4−y and a Li 3−2z BO 3−z compound, wherein 0<y<1.5 and 0<z<1.5.

5. The cathode active material of claim 1 , wherein the glassy coating compound has a composition gradient, wherein the value of x at the surface of the primary particles is lower than the value of x at the outer surface of the glassy coating.

6. The cathode active material of claim 1 , wherein the cathode active material comprises between 0.07 and 1 wt % of Si.

7. The cathode active material of claim 2 , wherein the cathode active material comprises between 0.1 and 2 wt % P.

8. The cathode active material of claim 2 , wherein the cathode active material comprises between 0.03 and 0.5 wt % B.

9. The cathode active material of claim 1 , wherein the glassy surface coating consists of nano-composites of Li 2 Si 5 O 11 and Li 2 SiO 3 particles.

10. The cathode active material of claim 1 , wherein the cathode active material comprises between 0.05 and 0.5 mol % glassy surface coating.

11. The cathode active material of claim 1 , wherein the primary particles are either one of
Li a Ni x′ CO y′ N z′ O 2±e A f , with 0.9<a<1.1, 0.5<x′≤0.9, 0<y′<0.4, 0<z′<0.35, e<0.02, 0<f<0.05 and 0.9<(x′+y′+z′+f)<1.1; N consisting of one or more elements selected from the group consisting of Al, Mg, and Ti; and A consisting of one or both of S and C; and
Li 1+a′ M′ 1-a′ O 2±b M″ k S m with −0.03<a′<0.06, b<0.02, wherein at least 95% of M′=Ni a″ Mn b″ Co c″ , with a″>0, b″>0, c″>0 and a″+b″+c″=1; and a″/b″>1; wherein M″ consists of one or more elements selected from the group consisting of Ca, Sr, Y, La, Ce and Zr, with 0<k<0.1 in wt %; and wherein 0<m≤0.6, m being expressed in mol %.

12. The cathode active material of claim 11 , wherein the primary particles are Li 1+a′ M′ 1-a′ O 2±b M″ k S m with M′=Ni a″ Mn b″ Co c″ , and wherein 1.5<a″/b″<3, and 0.1≤c″<0.35.

13. The cathode active material according to claim 12 , wherein 0.5<a″<0.7.

14. A method for preparing the cathode active material of claim 1 , comprising:
providing a lithium transition metal based oxide powder,
providing an alkali mineral compound comprising a Li 2−x SiO 3−0.5x compound, wherein 0<x<2,
mixing the lithium transition metal based oxide powder and the alkali mineral compound to form a powder-mineral compound mixture, and
heat treating the mixture at a temperature T between 300 and 500° C., whereby a glassy surface coating is formed comprising a Li 2−x″ SiO 3−0.5x′ compound, wherein x<x″<2.

15. The method according to claim 14 , wherein the heat treatment is performed in an oxygen comprising atmosphere.

16. The method according to claim 14 , wherein the alkali mineral compound is provided as a dry nanometric powder; and during the heat treatment of the mixture, the powder is sintered and adheres to a surface of the transition metal based oxide powder in the form of a glassy coating.

17. The method according to claim 14 , wherein the alkali mineral compound is provided as an aqueous solution of the alkali mineral compound; and during the heat treatment of the mixture, water from the aqueous solution evaporates and the compound dries to form a glassy coating on a surface of the metal based oxide powder.

18. The method according to claim 14 , wherein the lithium transition metal based oxide powder consists of either one of
Li a Nix′Co y′ Nz′O 2±e A f , with 0.9<a<1.1, 0.5<x′<0.9, 0<y′<0.4, 0<z′<0.35, e<0.02, 0<f<0.05 and 0.9<(x′+y′+z′+f)<1.1; N consisting of one or more elements selected from the group consisting of Al, Mg, and Ti; and A consisting of one or both of S and C; and
Li 1+a′ M′ 1-a′ O 2±b M″ k S m with −0.03<a′<0.06, b<0.02, wherein at least 95% of M′=Ni a″ Mn b″ Co c″ , with a″>0, b″>0, c″>0 and a″+b″+c″=1; and a″/b″>1; wherein M″ consists of one or more elements selected from the group consisting of Ca, Sr, Y, La, Ce and Zr, with 0<k<0.1 in wt %; and wherein 0≤m<0.6, m being expressed in mol %.

19. The method according to claim 18 , wherein the lithium transition metal based oxide powder consists of Li 1+a′ M′ 1-a′ O 2±b M″ k S m with M′=Ni a″ Mn b″ Co c″ , and wherein 1.5<a″/b″<3, and 0.1≤c″<0.35.

20. The method according to claim 19 , wherein 0.5≤a″<0.7.

21. The method according to claim 14 , wherein the alkali mineral compound consists of Li 2 Si 5 O 11 or Li 2 Si 2 O 5 .

22. The method according to claim 14 , wherein the heat treatment of the mixture is performed at a temperature T between 350 and 450° C. for at least one hour.

Assignees

• Paulsen Jens
• De Palma Randy
• Kim Jihye
• Umicore Nv

Inventors

• Paulsen Jens
• De Palma Randy
• Kim Jihye

Classifications

• C04B35/62886

  by wet chemical techniques · CPC title

• C04B2235/447

  Phosphates or phosphites, e.g. orthophosphate or hypophosphite · CPC title

• C01B33/32

  Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence) · CPC title

• C04B2235/3229

  Cerium oxides or oxide-forming salts thereof · CPC title

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title