Graphene-enhanced anode particulates for lithium ion batteries

• US 20120064409A1
• Filed: 09/10/2010
• Published: 03/15/2012
• Est. Priority Date: 09/10/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Nanotek Instruments, Inc.
• Inventors: Zhamu, Aruna, Shi, Jinjun, Chen, Guorong, Jang, Bor Z., Fang, Qing
• Granted Patent: US 9,558,860 B2
• Time in Patent Office: Days
• US Class Current: 429/221
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01B 1/04 mainly consisting of carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• 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 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/139 Processes of manufacture
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/387 Tin or alloys based on tin
• CPC Class Codes: H01M 4/48 of inorganic oxides or hydroxides
• CPC Class Codes: H01M 4/483 for non-aqueous cells H01M4/485 takes precedence
• CPC Class Codes: H01M 4/523 for non-aqueous cells H01M4/525 takes precedence
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A nano graphene-enhanced particulate for use as a lithium-ion battery anode active material, wherein the particulate is formed of a single sheet of graphene or a plurality of graphene sheets and a plurality of fine anode active material particles with a size smaller than 10 μm. The graphene sheets and the particles are mutually bonded or agglomerated into the particulate with at least a graphene sheet embracing the anode active material particles. The amount of graphene is at least 0.01% by weight and the amount of the anode active material is at least 0.1% by weight, all based on the total weight of the particulate. A lithium-ion battery having an anode containing these graphene-enhanced particulates exhibits a stable charge and discharge cycling response, a high specific capacity per unit mass, a high first-cycle efficiency, a high capacity per electrode volume, and a long cycle life.

Claims

1. A nano graphene-enhanced particulate for use as a lithium-ion battery anode active material, wherein said particulate is formed of a single or a plurality of graphene sheets and a plurality of fine anode active material particles with a size smaller than 10 μ

m, and the graphene sheets and the particles are mutually bonded or agglomerated into said particulate with at least a graphene sheet embracing said anode active material particles, and wherein said graphene is in an amount of at least 0.01% but less than 99% by weight and said anode active material is in an amount of at least 0.1% by weight, all based on the total weight of said particulate.

2. The particulate of claim 1 wherein the graphene amount is at least 0.1% by weight.

3. The particulate of claim 1 wherein the graphene amount is at least 1% by weight.

4. The particulate of claim 1 wherein said particulate is spherical or ellipsoidal in shape.

5. The particulate of claim 1 wherein said graphene comprises single-layer graphene or few-layer graphene, wherein said few-layer graphene is defined as a graphene platelet formed of less than 10 graphene planes.

6. The particulate of claim 1, wherein said anode active material comprises Sn or Si as a primary element with Si or Sn content no less than 20% by weight based on the total weight of the anode active material.

7. The particulate of claim 1, wherein said anode active material comprises an element selected from Si, Ge, Sn, Cd, Sb, Pb, Bi, Zn, Al, Co, Ni, or Ti.

8. The particulate of claim 1, wherein said anode active material is selected from the group consisting of:

(g) silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd);

(h) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements, wherein said alloys or compounds are stoichiometric or non-stoichiometric;

(i) oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Fe, Ni, Co, or Cd, and their mixtures, composites, or lithium-containing composites;

(j) salts and hydroxides of Sn;

(k) lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxide, lithium transition metal oxide; and

(l) combinations thereof.

9. The particulate of claim 1, wherein said anode active material particles in a particulate have a dimension smaller than 1 μ

m.

10. The particulate of claim 1, wherein said anode active material particles in a particulate have a dimension smaller than 100 nm.

11. The particulate of claim 1, further comprising a carbon or graphite material in electronic contact with said anode active material and a graphene sheet.

12. The particulate of claim 1, further comprising a carbon or graphite material coated on or in contact with at least one of said anode active material particles, wherein said carbon or graphite material is selected from polymeric carbon, amorphous carbon, chemical vapor deposition carbon, coal tar pitch, petroleum pitch, meso-phase pitch, carbon black, coke, acetylene black, activated carbon, fine expanded graphite particle with a dimension smaller than 100 nm, artificial graphite particle, natural graphite particle, or a combination thereof

13. The particulate of claim 12, wherein said polymeric carbon or amorphous carbon is obtained from pyrolyzation of a polymer selected from the group consisting of phenol-formaldehyde, polyacrylonitrile, styrene-based polymers, cellulosic polymers, epoxy resins, and combinations thereof.

14. The particulate of claim 1, wherein said anode active material is selected from lithiated titanium dioxide, lithiated titanium oxide, lithium titanate, or Li₄Ti₅O₁₂.

15. The particulate of claim 1 wherein said anode active material is selected from natural graphite, artificial graphite, meso-carbon micro-bead (MCMB), graphitic coke, meso-phase carbon, hard carbon, soft carbon, polymeric carbon, carbon or graphite fiber segments, carbon nano-fiber or graphitic nano-fiber, carbon nano-tube, or a combination thereof.

16. The particulate of claim 1, wherein said particulate is prepared from a process comprising:

(a) Preparing a precursor mixture of graphene or graphene precursor with an anode active material or anode active material precursor; and

(b) Thermally and/or chemically converting said precursor mixture to said graphene-enhanced anode particulate.

17. The particulate of claim 16, wherein said step of preparing a precursor mixture comprises preparing a suspension of graphene or graphene precursor in a liquid medium and mixing an anode active material or anode active material precursor in said suspension to form a multi-component suspension.

18. The particulate of claim 17, wherein the process further comprises a step of drying said multi-component suspension to form said precursor mixture.

19. The particulate of claim 17, wherein the process further comprises a step of drying said multi-component suspension to form said precursor mixture using a spray-drying, spray-pyrolysis, fluidized-bed drying, or atomization or aerosolizing step.

20. The particulate of claim 16, wherein said step of converting comprises a sintering, heat-treatment, spray-pyrolysis, or fluidized bed drying or heating procedure.

21. The particulate of claim 16, wherein said step of converting comprises a procedure of chemically or thermally reducing said graphene precursor to reduce or eliminate oxygen content and other non-carbon elements of said graphene precursor.

22. The particulate of claim 1, wherein said graphene precursor contains graphene oxide or graphene fluoride.

23. The particulate of claim 1 wherein said graphene in said particulate has an oxygen content less than 5% by weight.

24. The particulate of claim 16, wherein said step of preparing said precursor mixture comprises:

A) dispersing or exposing a laminar graphite material in a fluid of an intercalant and/or an oxidant to obtain a graphite intercalation compound (GIC) or graphite oxide (GO);

B) exposing the resulting GIC or GO to a thermal shock at temperature for a period of time sufficient to obtain exfoliated graphite or graphite worms;

C) dispersing the exfoliated graphite or graphite worms in a liquid medium containing an acid, an oxidizing agent, and/or an organic solvent at a desired temperature for a duration of time until the exfoliated graphite is converted into a graphene oxide dissolved in the liquid medium to form a graphene solution; and

D) adding a desired amount of said anode precursor material to said graphene solution to form said precursor mixture in a suspension, slurry or paste form.

25. The particulate of claim 16, wherein said step of preparing said precursor mixture comprises:

(a) preparing a suspension containing pristine nano graphene platelets (NGPs) dispersed in a liquid medium;

(b) adding an acid and/or an oxidizing agent into said suspension at a temperature for a period of time sufficient to obtain a graphene solution or suspension; and

(c) adding a desired amount of an anode active material or precursor in the graphene solution or suspension to form a paste or slurry.

26. A lithium ion battery anode comprising multiple nano graphene-enhanced anode particulates of claim 1.

27. A lithium ion battery anode comprising multiple nano graphene-enhanced anode particulates of claim 12.

28. A lithium ion battery anode comprising multiple nano graphene-enhanced anode particulates of claim 14.

29. A lithium ion battery comprising an anode of claim 26, a cathode, a separator disposed between the anode and the cathode, and electrolyte in physical contact with both the anode and the cathode.

30. A lithium ion battery comprising an anode of claim 27, a cathode, a separator disposed between the anode and the cathode, and electrolyte in physical contact with both the anode and the cathode.

31. A lithium ion battery comprising an anode of claim 28, a cathode, a separator disposed between the anode and the cathode, and electrolyte in physical contact with both the anode and the cathode.

32. A lithium ion battery of claim 29, wherein said cathode comprises a graphene-enhanced cathode particulate formed of a single or a plurality of graphene sheets and a plurality of fine cathode active material particles with a size smaller than 10 μ

m, and the graphene sheets and the particles are mutually bonded or agglomerated into said cathode particulate with at least a graphene sheet embracing said cathode active material particles, and wherein said graphene is in an amount of from 0.01% to 30% by weight based on the cathode particulate weight.

33. The lithium ion battery of claim 32, wherein said cathode active material particles have a size smaller than 1 μ

m.

34. The lithium ion battery of claim 32, wherein said cathode active material particles have a size smaller than 100 nm.

35. The lithium ion battery of claim 32, wherein said cathode active material is selected from the group consisting of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium vanadium oxide, lithium-mixed metal oxide, lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium mixed metal phosphates, metal sulfides, and combinations thereof.