Lithium super-battery with a functionalized nano graphene cathode

• US 20120045688A1
• Filed: 08/19/2010
• Published: 02/23/2012
• Est. Priority Date: 08/19/2010
• Status: Active Grant

• Current Assignee: Honeycomb Battery Co. (Global Graphene Group, Inc.)
• Original Assignee: Nanotek Instruments, Inc.
• Inventors: Zhamu, Aruna, Neff, David, Jang, Bor Z., Liu, Chenguang
• Granted Patent: US 8,795,899 B2
• Time in Patent Office: Days
• US Class Current: 429/207
• CPC Class Codes: H01G 11/06 with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
• CPC Class Codes: H01G 11/38 Carbon pastes or blends; Binders or additives therein
• CPC Class Codes: H01G 11/50 specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
• 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 4/587 for inserting or intercalating light metals
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An electrochemical energy storage device, lithium super-battery, comprising a positive electrode, a negative electrode, a porous separator disposed between the two electrodes, and a lithium-containing electrolyte in physical contact with the two electrodes, wherein the positive electrode comprises a plurality of chemically functionalized nano graphene platelets (f-NGP) or exfoliated graphite having a functional group that reversibly reacts with a lithium atom or ion. In a preferred embodiment, a lithium super-battery having a f-NGP positive electrode and Li₄Ti₅O₁₂ negative electrode exhibits a gravimetric energy ˜5 times higher than conventional supercapacitors and a power density ˜10 times higher than conventional lithium-ion batteries. This device has the best properties of both the lithium ion battery and the supercapacitor.

Claims

1. An electrochemical energy storage device comprising a positive electrode, a negative electrode, a porous separator disposed between the two electrodes, and a lithium-containing electrolyte in physical contact with the two electrodes, wherein the positive electrode comprises a plurality of chemically functionalized nano graphene platelets or exfoliated graphite having a functional group that reversibly reacts with a lithium atom or ion.

2. The electrochemical device of claim 1 wherein said nano graphene platelets or exfoliated graphite have a functional group selected from —

COOH, ═

O, —

OH, —

NH₂, an oxygen-containing group attached to a carbon atom at a graphene platelet, —

OR, or —

COOR, where R is a hydrocarbon radical.

3. The electrochemical device of claim 1 wherein said negative electrode comprises an electrode active material capable of absorbing or desorbing lithium.

4. The electrochemical device of claim 1 wherein said positive electrode comprises nano graphene platelets or exfoliated graphite having a functional group selected from —

COOH, ═

O, —

OH, —

NH₂, —

OR, —

COOR, or an oxygen-containing group attached to a carbon atom at a graphene platelet, where R is a hydrocarbon radical and wherein the negative electrode comprises an electrode active material capable of absorbing or desorbing lithium.

5. The electrochemical device of claim 3 wherein said electrode active material is selected from lithium metal, a lithium metal alloy, a mixture of lithium metal or lithium alloy with a lithium intercalation compound, a lithiated compound, lithiated titanium dioxide, lithium titanate, lithium manganate, a lithium transition metal oxide, Li₄Ti₅O₁₂, or a combination thereof.

6. The electrochemical device of claim 5, wherein the lithium intercalation compound is selected from the following groups of materials, which are capable of absorbing or desorbing lithium ions or atoms:

(a) Silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), Titanium (Ti), cadmium (Cd), and mixtures thereof;

(b) Alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, or Cd;

(c) Oxides, carbides, nitrides, sulfides, phosphides, selenides, tellurides, or antimonides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Fe, Ti, Mn, or Cd and mixtures or composites thereof; and

(d) Salts or hydroxides of Sn.

7. The electrochemical device of claim 4 wherein said electrode active material is selected from lithium metal, a lithium metal alloy, a mixture of lithium metal or lithium alloy with a lithium intercalation compound, a lithiated compound, lithiated titanium dioxide, lithium titanate, lithium manganate, a lithium transition metal oxide, Li₄Ti₅O₁₂, or a combination thereof.

8. The electrochemical device of claim 7, wherein the lithium intercalation compound is selected from the following groups of materials, which are capable of absorbing or desorbing lithium ions or atoms:

(a) Silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), Titanium (Ti), cadmium (Cd), and mixtures thereof;

(b) Alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, or Cd;

(c) Oxides, carbides, nitrides, sulfides, phosphides, selenides, tellurides, or antimonides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Fe, Ti, Mn, or Cd and mixtures or composites thereof; and

(d) Salts or hydroxides of Sn

9. The electrochemical device of claim 5 wherein said electrode active material is in a fine powder form having a dimension less than 1 μ

m.

10. The electrochemical device of claim 7 wherein said electrode active material is in a fine powder form having a dimension less than 0.5 μ

m.

11. The electrochemical device of claim 7 wherein said electrode active material is in a fine powder form having a dimension less than 100 nm.

12. The electrochemical device of claim 3 wherein said electrode active material is selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, lithium vanadium oxide, lithium mixed metal oxide, lithium iron phosphate, lithium vanadium phosphate, lithium manganese phosphate, a lithium transition metal phosphate, lithium mixed metal phosphate, lithiated metal sulfide, or a combination thereof.

13. The electrochemical device of claim 4 wherein said electrode active material is selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, lithium vanadium oxide, lithium mixed metal oxide, lithium iron phosphate, lithium vanadium phosphate, lithium manganese phosphate, a lithium transition metal phosphate, lithium mixed metal phosphate, lithiated metal sulfide, or a combination thereof.

14. The electrochemical device of claim 12 wherein said electrode active material is in a fine powder form having a dimension less than 0.5 μ

m.

15. The electrochemical device of claim 13 wherein said electrode active material is in a fine powder form having a dimension less than 100 nm.

16. The electrochemical device of claim 1 wherein said nano graphene platelets or exfoliated graphite have an oxygen content in the range of 5% to 45% by weight based on the total graphene platelet weight.

17. The electrochemical device of claim 1 wherein said nano graphene platelets or exfoliated graphite have an oxygen content in the range of 5% to 25% by weight based on the total graphene platelet weight.

18. The electrochemical device of claim 1 wherein said nano graphene platelets or exfoliated graphite have an oxygen content in the range of 10% to 20% by weight based on the total graphene platelet weight.

19. The electrochemical device of claim 1 wherein said electrolyte comprises a lithium salt-doped ionic liquid.

20. The electrochemical device of claim 1 wherein said nano graphene platelets comprise single-layer graphene.

21. The electrochemical device of claim 1 wherein said nano graphene platelets comprise a few-layer graphene platelet formed of 2-10 graphene planes.

22. The electrochemical device of claim 1 wherein said nano graphene platelets comprise a few-layer graphene platelet formed of 3-7 graphene planes.

23. The electrochemical device of claim 1 wherein said nano graphene platelets comprise curved graphene platelets.

24. The electrochemical device of claim 1 wherein at least one of the two electrodes further comprises a nano material selected from a carbon nano-tube, carbon nano-fiber, activated carbon, carbon black, nano-wire, metal oxide nano-wire or fiber, conductive polymer nano-fiber, or a combination thereof.

25. The electrochemical device of claim 1 wherein said device provides an energy density of no less than 200 Wh/kg and power density no lower than 45 Kw/kg, all based on the total electrode weight.

26. The electrochemical device of claim 1 wherein said device provides an energy density of no less than 300 Wh/kg and power density no lower than 25 Kw/kg, all based on the total electrode weight.

27. The electrochemical device of claim 1 wherein said device provides an energy density of no less than 500 Wh/kg and power density no less than 15 Kw/kg, all based on the total electrode weight.

28. The electrochemical device of claim 1 wherein said positive electrode has a thickness greater than 10 μ

m.

29. The electrochemical device of claim 1 wherein said positive electrode has a thickness greater than 50 μ

m.

30. The electrochemical device of claim 1 wherein said positive electrode has a thickness greater than 100 μ

m.