Cathode formed using aqueous slurry
In one embodiment, a positive electrode is formed by a process that includes forming a slurry including particles dispersed within a liquid from a electrode formulation and the liquid such that the particles have a particle size distribution D 50 of 15 microns or less, coating the slurry on a collector; and drying the coated collector to form the positive electrode. The electrode formulation includes an electrode active material, a conductive carbon source, an organic polymeric binder, and a water-soluble polymer. The liquid consists essentially of water or a mixture of water and an alcohol. When the liquid consists essentially of the mixture, the alcohol is present in an amount of less than 10% by weight, based on the weight of the slurry. When the liquid consists essentially of water, the slurry is formed from the electrode formulation, the liquid, and an arene-capped polyoxoethylene surfactant.
1. A method of making a positive electrode, comprising:
forming a slurry from an electrode formulation, an additive comprising an arene-capped polyoxoethylene surfactant, and a liquid such that the slurry comprises particles of the electrode formulation dispersed within the liquid, wherein the particles of the electrode formulation have a particle size distribution D 50 of 15 microns or less in the slurry;
coating the slurry on a collector; and
drying the coating on the collector to form the positive electrode,
wherein the electrode formulation comprises a lithium-nickel-manganese-cobalt composite oxide as at least one electrode active material, a conductive carbon source, an organic polymeric binder, and a water-soluble polymer, and wherein the liquid consists essentially of water.
2. The method of claim 1 , wherein the arene-capped polyoxoethylene is present in an amount of between 0.05% by weight and 0.5% by weight, based on the weight of the slurry.
3. The method of claim 1 , wherein the arene-capped polyoxoethylene has the general formula Ar—O(C 2 H 4 O) n , wherein Ar is an aromatic group or a substituted aromatic group and n is an integer greater than 4.
4. The method of claim 1 , wherein the arene-capped polyoxoethylene has the general formula:
wherein R 1 is an alkyl group having between 1 and 14 carbons and n is an integer greater than 4.
5. The method of claim 1 , wherein the arene-capped polyoxoethylene has the general formula:
wherein n is an integer greater than 4.
6. The method of claim 1 , wherein the particles have a particle size distribution D 75 of 10 microns or less.
7. The method of claim 1 , wherein the electrode formulation consists essentially of the electrode active material, the conductive carbon source, the organic polymeric binder, and the water-soluble polymer, wherein:
the conductive carbon source is present in an amount of less than 4% by weight, based on the total weight of the electrode formulation;
the organic copolymer binder is present in an amount between 1.0% by weight and 1.5% by weight, based on the total weight of the electrode formulation;
the water-soluble polymer is present in an amount between 0.5% by weight and 1.0% by weight, based on the total weight of the electrode formulation; and
the at least one electrode active material is present in an amount between 93.5% by weight and 94.5% by weight, based on the total weight of the electrode formulation.
8. The method of claim 7 , wherein the conductive carbon source is carbon black, the organic polymer binder is a monovinylarene-conjugated diene copolymer, and the water soluble polymer is a cellulose derivative.
9. The method of claim 1 , wherein the particles of the electrode formulation have a particle size distribution D 50 of between 14 microns and 6 microns.
10. The method of claim 1 , wherein the particles of the electrode formulation have a particle size distribution D 50 of between 12 microns and 6 microns.
11. The method of claim 1 , wherein the particles of the electrode formulation have a particle size distribution D 50 of between 10 microns and 6 microns.
12. A positive electrode formed by a process, the process comprising:
forming a slurry from an electrode formulation and a liquid such that the slurry comprises particles of the electrode formulation dispersed within the liquid, wherein the particles of the electrode formulation have a particle size distribution D 50 of 15 microns or less when the particles of the electrode formulation are dispersed in the slurry;
coating the slurry on a collector; and
drying the coated collector to form the positive electrode,
wherein the electrode formulation comprises at least one electrode active material, a conductive carbon source, an organic polymeric binder, and a water-soluble polymer, and wherein the liquid consists essentially of water or a mixture of water and an alcohol, wherein when the liquid consists essentially of the mixture, the alcohol is present in an amount of less than 10% by weight, based on the weight of the slurry, and wherein when the liquid consists essentially of water, the slurry is formed from the electrode formulation, the liquid, and an arene-capped polyoxoethylene surfactant.
13. The positive electrode of claim 12 , wherein the liquid consists essentially of the mixture, and the alcohol consists essentially of 1-propanol in an amount between 3% by weight and 7% by weight, based on the weight of the slurry.
14. The positive electrode of claim 12 , wherein the liquid consists essentially of water, and the arene-capped polyoxoethylene surfactant has the general formula:
wherein n is an integer greater than 4, and the arene-capped polyoxoethylene surfactant is present in an amount of between 0.05% by weight and 0.5% by weight, based on the weight of the slurry.
15. The positive electrode of claim 12 , wherein the electrode formulation consists essentially of the at least one electrode active material, the conductive carbon source, the organic polymeric binder, and the water-soluble polymer, wherein:
the conductive carbon source is carbon black present in an amount of less than 4% by weight, based on the total weight of the electrode formulation;
the organic polymeric binder is a monovinylarene-conjugated diene copolymer rubber present in an amount between 1.0% by weight and 1.5% by weight, based on the total weight of the electrode formulation;
the water-soluble polymer is a cellulose derivative present in an amount between 0.5% by weight and 1.0% by weight, based on the total weight of the electrode formulation; and
the electrode active material is a lithium-nickel-manganese-cobalt composite oxide present in an amount between 93.5% by weight and 94.5% by weight, based on the total weight of the electrode formulation.
16. The positive electrode of claim 12 , wherein the particles of the electrode formulation have a particle size distribution D 50 of between 14 microns and 6 microns.
17. The positive electrode of claim 12 , wherein the particles of the electrode formulation have a particle size distribution D 50 of between 12 microns and 6 microns.
18. The positive electrode of claim 12 , wherein the particles of the electrode formulation have a particle size distribution D 50 of between 10 microns and 6 microns.