Electrode composition for a secondary battery cell

• US 9,853,292 B2
• Filed: 10/26/2012
• Issued: 12/26/2017
• Est. Priority Date: 05/11/2009
• Status: Active Grant

• Current Assignee: SK On Company Limited (SK Innovation Company Limited)
• Original Assignee: Nexeon Limited
• Inventors: Loveridge, Melanie J., Lain, Michael Jonathan, Coowar, Fazil, Abdelsalam, Mamdouh Elsayad
• Primary Examiner(s): Slifka, Sarah A
• Assistant Examiner(s): Ohara, Brian
• Application Number:
  US14/353,730
• Publication Number:
  US 20140335410A1
• Time in Patent Office: 1,887 Days
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/362 Composites
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Disclosed are a composite electrode material for a rechargeable battery; a method of making a composite electrode material; an electrode including the composite electrode material; cells including such electrodes; and devices including the cells. A composite electrode material for a rechargeable battery cell includes an electroactive material; and a polymeric binder including pendant carboxyl groups. The electroactive material includes one or more components selected from the group including an electroactive metal, an electroactive semi-metal, an electroactive ceramic material, an electroactive metalloid, an electroactive semi-conductor, an electroactive alloy of a metal, an electroactive alloy of a semi-metal and an electroactive compound of a metal or a semi-metal. The polymeric binder has a molecular weight in the range 300,000 to 3,000,000. 40 to 90% of the carboxyl groups of the binder are in the form of a metal ion carboxylate salt.

Claims

1. A composite electrode material for a rechargeable battery cell, comprising:

a. an electroactive material comprising silicon; and

b. a polymeric binder comprising metal ion carboxylate groups and free carboxyl groups, the binder comprising partially neutralized polyacrylic acid;

characterized in that

i) the polymeric binder has a number average molecular weight in the range 300,000 to 3,000,000;

ii) the ratio of the number of metal ion carboxylate groups of the polymeric binder to the sum of the number of metal ion carboxylate groups of the polymeric binder and free carboxyl groups of the polymeric binder is 0.40-0.90; and

iii) the metal ions of the metal ion carboxylate groups are sodium ions.

2. A composite electrode material according to claim 1, in which the ratio of the number of metal ion carboxylate groups of the polymeric binder to the sum of the number of metal ion carboxylate groups of the polymeric binder and free carboxyl groups of the polymeric binder is 0.60-0.80.

3. A composite electrode material according to claim 1, which further comprises an electroactive carbon selected from graphite, hard carbon, carbon microbeads and graphene, wherein the electroactive carbon constitutes 0 to 70 percent by weight of the total weight of the electroactive materials of the composite electrode material.

4. A composite electrode material according to claim 3, wherein the electroactive material and the electroactive carbon together constitute at least 50 percent by weight of the composite electrode material.

5. A composite electrode material according to claim 1, which comprises 0.5 to 15 percent by weight of the polymeric binder.

6. A composite electrode material according to claim 1, which further comprises 4 to 16 percent by weight of a conductive carbon selected from one or more of carbon black, acetylene black, ketjen black, lamp black, carbon nano-tubes and vapour grown carbon fibres.

7. A composite electrode material according to claim 1, wherein the electroactive material is a structured electroactive material selected from one or more of the structure group consisting of particles, elongate elements, pillared particles, porous particles, porous particle fragments, substrate particles, bundles of elongate elements, and scaffold structures.

8. A composite electrode material according to claim 1, wherein the electroactive material comprises an elongate element selected from the group consisting of fibres, threads, pillars, wires, nano-wires, filaments, tubes, ribbons and flakes.

9. A composite electrode material according to claim 8, wherein the fibre, thread, pillar, filament or wire has an aspect ratio in the range of 5:

1 to 1000;

1.

10. A composite electrode material according to claim 1, wherein the electroactive material comprises particles having a diameter in the range 1 μ

m to 20 μ

m.

11. A composite electrode material according to claim 1, wherein the electroactive material is selected from a ribbon, a flake and a tube having a first dimension in the range of 0.03 μ

m to 2 μ

m.

12. A composite electrode material according to claim 1, wherein the electroactive material comprises a pillared particle having an overall diameter in the range 5 to 30 μ

m and/or a porous particle having a plurality of voids or channels extending therethrough having a maximum diameter of 1 to 40 μ

m.

13. An electrode for a rechargeable battery comprising a current collector and a composite electrode material according to claim 1.

14. An electrode according to claim 13, wherein the composite electrode material is in the form of a layer adhered to the current collector, said composite electrode material having a thickness of at least 6 μ

m and no more than 60 μ

m.

15. An electrode according to claim 13, wherein the composite electrode material has a porosity of at least 10% and no more than 60% in the uncharged state.

16. A cell comprising an electrode according to claim 13 comprising a composite electrode material, a cathode, a separator and an electrolyte.

17. A cell according to claim 16, wherein the composite electrode material of the electrode forms a gel on contact with the electrolyte.

18. A device comprising a cell according to claim 16.

19. A composite electrode material according to claim 1, wherein the electroactive material is silicon or an alloy thereof.

20. A composite electrode material according to claim 1, wherein the electroactive material is silicon of at least 90% purity.

21. A composite electrode material according to claim 1, wherein the composite electrode material comprises at least 50 wt % of the electroactive material and 3-40% of the polymeric binder.

22. A composite electrode material according to claim 6, wherein the conductive carbon is a mixture of carbon nano-tubes, carbon nano-fibres and carbon black.

23. A composite material according to claim 1, wherein the electroactive material comprising silicon further comprises one or more of an organic polymer, a ceramic material, an inorganic semi-conductor and a biologically derived compound.

24. A composite electrode material according to claim 7, wherein the porous particles comprise a random or ordered network of linear, branched or elongate elements, wherein one or more discrete or interconnected void spaces or channels are defined between the elongate elements of the network.

25. A composite electrode material according to claim 7, wherein the elongate elements include structures in which the elongate elements are fused together.

26. A composite electrode material according to claim 1, wherein the electroactive material comprising silicon further comprises one or more carbon materials selected from an amorphous carbon, graphite, electroactive hard carbon, conductive carbon, carbon-based polymers and carbon black, or a conductive ceramic.

27. A composite electrode material according to claim 1, wherein the electroactive silicon material is selected from one or more of a coated particle, a coated pillared particle, a coated porous particle and a coated porous particle fragment.

28. A composite electrode material according to claim 1, wherein the binder further comprises one or more binder species selected from PVDF, SBR, CMC and sodium CMC.