Lithium ion batteries

Patent metadata

Field	Value
Publication number	US-2016149205-A1
Application number	US-201414899779-A
Country	US
Kind code	A1
Filing date	Jun 26, 2014
Priority date	Jul 9, 2013
Publication date	May 26, 2016
Grant date	—

Abstract

An improved method of making a cathode for use in a lithium ion battery is comprised of mixing a lithium metal oxide and lithium metal phosphate in a solvent, where both of these are comprised of primary particles that have been agglomerated into secondary particles of particular size and mixing is insufficient to break up the particles of the lithium metal phosphate, coating the mixture of step (A) on to a metal foil and removing the solvent to form the cathode. The lithium metal oxide is also desirably not broken either. The cathode may be one that has lithium metal oxide and a particular lithium metal phosphate wherein the majority of the metal is Mn.

First claim

1 . A method of forming a cathode comprising:
(a) mixing a lithium metal oxide and lithium metal phosphate in a solvent, wherein (i) the lithium metal phosphate has a D50secondary particle size by number of 2 micrometers to 30 micrometers and a D50primary particle size by number that is 25 to 1000 nanometers, (ii) the lithium metal oxide has a secondary particle size having a D50by number of 2 to 30 micrometers and, (iii) the mixing is insufficient to break up the secondary particles of the lithium metal phosphate, (b) coating the mixture of step (A) on to a metal foil; and (c) removing the solvent to form the cathode.

2 . The method of claim 1 , further comprising pressing the cathode after removing the solvent.

3 . The method of claim 2 , wherein the pressing is performed at a pressure insufficient to deform or break the lithium metal oxide secondary particles, but sufficient to deform the lithium metal phosphate secondary particulates.

4 . The method of claim 3 , wherein the pressing is performed at a pressure from 10 MPa to 250 MPa.

5 . The method of claim 4 , wherein the average sphericity of the lithium metal oxide is from 0.4 to 1.0 and the average sphericity of the lithium metal phosphate is from 0.4 to 1.0.

6 . The method of claim 5 , wherein the average sphericity of the lithium metal oxide to the average sphericity of the lithium metal phosphate has a ratio that is 0.4 to 2.5.

7 . The method of claim 1 , wherein the mixing has a shear rate of at most 5000sec −1 .

8 . The method of claim 1 , wherein the lithium metal oxide has a D50primary particle size of 3 micrometers to 0.1 micrometers.

9 . The method of claim 1 , wherein the D50secondary particle size of the lithium metal phosphate to the D50secondary particle size of the lithium metal oxide has a ratio that is 0.25 to 1.5.

10 . A cathode comprised of a metal foil having a first and second face and cathode material coated on at least one face of the foil, the cathode material being comprised of a mixture of a lithium metal oxide and a lithium metal phosphate wherein the amount of lithium metal phosphate is 5% to 65% by weight of the mixture, wherein the lithium metal oxide is comprised of primary and secondary particles and the lithium metal phosphate is comprised of primary and secondary particles and the lithium metal oxide secondary particles have a D50by number and lithium metal phosphate secondary particles have a D50by number such that the D50secondary particle size of the lithium metal oxide and lithium metal phosphate has a ratio of between 0.25 to 1.5.

11 . The cathode of claim 8 , wherein the lithium metal phosphate has an electronic conductive coating.

12 . The cathode of claim 9 , wherein lithium metal oxide has an electronic conductive coating that is graphite, amorphous carbon or combination thereof.

13 . The cathode of claim 8 , wherein the average sphericity of the lithium metal oxide is from 0.4 to 1.0 and the average sphericity of the lithium metal phosphate is from 0.4 to 1.0.

14 . The cathode of claim 13 , wherein the average sphericity of the lithium metal oxide to the average sphericity of the lithium metal phosphate has a ratio 0.4 to 2.5.

15 . A cathode comprised of a metal foil having a first and second face and cathode material coated on at least one face of the foil, the cathode material being comprised of a mixture of lithium metal oxide and lithium metal phosphate wherein the amount of lithium metal phosphate is 5% to 49% by wight of the mixture and the lithium metal phosphae has the formula Li a Mn b Fe c D d PO 4 , wherein
a is number from 0.85 to 1.15; b is from 0.51 to 0.95; c is from 0.05 to 0.49; d is from 0.000 to 0.1;
D being a metal ion selected from one or more of magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum and the lithium metal phosphate has an electronic conductive coating thereon.

16 . The cathode of claim 15 , wherein the lithium metal phosphate has the formula Li a Mn b Fe c D d PO 4 , wherein
a is a number from 0.85 to 1.15; b is from 0.65 to 0.95; c is from 0.049 to 0.349; d is from 0.001 to 0.1;
2.75≦(a+2b+2c+dV)≦3.10, wherein V is the valence of D, and D is a metal ion selected from one or more of magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum, and further wherein at least a portion of the lithium metal phosphate has an olivine structure.

17 . The cathode of claim 16 , wherein D is magnesium, cobalt or a mixture of magnesium and cobalt.

18 . The cathode of claim 16 , wherein (a+2b+2c+dV)≢3.00.

19 . A lithium ion battery comprising the cathode of claim 10 .

Assignees

• Dow Global Technologies Llc

Inventors

• Theivanayagam Murali G
• Hu Ing-Feng
• Maeda Hideaki
• Lin Jui-Ching

Classifications

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M4/1391 Primary

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

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/131 Primary

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