Mixed nano-filament electrode materials for lithium ion batteries

• US 8,435,676 B2
• Filed: 01/09/2008
• Issued: 05/07/2013
• Est. Priority Date: 01/09/2008
• Status: Active Grant

• Current Assignee: Honeycomb Battery Co. (Global Graphene Group, Inc.)
• Original Assignee: Nanotek Instruments, Inc.
• Inventors: Zhamu, Aruna, Jang, Bor Z.
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): Mohaddes, Ladan
• Application Number:
  US12/008,118
• Publication Number:
  US 20090176159A1
• Time in Patent Office: 1,945 Days
• Field of Search: 429/222, 429/218.1, 429/225, 429/231, 429/231.8, 429/209
• US Class Current: 429/231.8
• 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 4/483 for non-aqueous cells H01M4/485 takes precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/58 of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
• 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: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

This invention provides a mixed nano-filament composition for use as an electrochemical cell electrode. The composition comprises: (a) an aggregate of nanometer-scaled, electrically conductive filaments that are substantially interconnected, intersected, or percolated to form a porous, electrically conductive filament network, wherein the filaments have a length and a diameter or thickness with the diameter/thickness less than 500 nm (preferably <100 nm) and a length-to-diameter or length-to-thickness aspect ratio greater than 10; and (b) Multiple nanometer-scaled, electro-active filaments comprising an electro-active material capable of absorbing and desorbing lithium ions wherein the electro-active filaments have a diameter or thickness less than 500 nm (preferably <100 nm). The electro-active filaments (e.g., nanowires) and the electrically conductive filaments (e.g., carbon nano fibers) are mixed to form a mat-, web-, or porous paper-like structure in which at least an electro-active filament is in electrical contact with at least an electrically conductive filament. Also provided is a lithium ion battery comprising such an electrode as an anode or cathode, or both. The battery exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

Claims

1. An electrochemical cell electrode comprising a mixed nano-filament composition, said composition comprising an aggregate of:

a) nanometer-scaled, electrically conductive filaments that are interconnected, intersected, or percolated to form a porous, electrically conductive filament network, wherein said filaments have a length and a diameter or thickness, and the diameter or thickness is less than 500 nm with a length-to-diameter or length-to-thickness aspect ratio greater than 10 and said conductive filaments are selected from nano-scaled graphene platelets with a length-to-width ratio greater than 3, metal nano wires, metal-coated fibrils, and combinations thereof; and

b) multiple nanometer-scaled, electro-active filaments comprising therein or thereon an electro-active material capable of absorbing and desorbing lithium ions wherein said electro-active filaments have a diameter or thickness less than 500 nm;

wherein the electro-active filaments comprise an active material selected from the group consisting of;

a) silicon (Si), germanium (Ge), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), and cadmium (Cd);

b) alloys or intermetallic compounds of Si, Ge, Pb, Sb, Bi, Zn, Al, or Cd with other elements, wherein said alloys or compounds are stoichiometric or non-stoichiometric;

c) oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Si, Ge, Pb, Sb, Bi, Zn, Al, Fe, or Cd, and their mixtures or composites; and

d) combinations thereof; and

wherein said electro-active filaments and said electrically conductive filaments are intertwined to form a mat, web, or porous paper structure in which at least an electro-active filament is in electrical contact with at least an electrically conductive filament.

2. The mixed nano-filament composition of claim 1 wherein said electrically conductive filaments have a diameter or thickness smaller than 100 nm or said electro-active filaments have a diameter or thickness smaller than 100 nm.

3. The mixed nano-filament composition of claim 1 wherein said electro-active filaments comprise nanowires and at least an electro-active filament is in electrical contact with electrically conductive filaments at multiple contact points.

4. The mixed nano-filament composition of claim 1 wherein said electrically conductive filaments comprise nano-scaled graphene platelets with a thickness less than 10 nm.

5. The mixed nano-filament composition of claim 1 wherein said electro-active filaments comprise a nanowire selected from the group consisting of nanowires of Ge, Si, their oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides, and combinations thereof.

6. The mixed nano-filament composition of claim 4 wherein said electro-active filaments comprise Si nanowires.

7. The mixed nano-filament composition of claim 5 wherein said electro-active filaments comprise Si nanowires.

8. The mixed nano-filament composition of claim 1 wherein the electro-active filaments comprise an element selected from Si, Ge, Sb, or a combination thereof.

9. The mixed nano-filament composition of claim 3 wherein the nanowires are amorphous or comprise nano crystallites.

10. A lithium secondary battery comprising a positive electrode (cathode), a negative electrode (anode) comprising a mixed nano-filament composition as defined in claim 1 which is capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between said negative electrode and said positive electrode.

11. A lithium secondary battery comprising a positive electrode, a negative electrode comprising a mixed nano-filament composition as defined in claim 2 which is capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between said negative electrode and said positive electrode.

12. A lithium secondary battery comprising a positive electrode, a negative electrode comprising a mixed nano-filament composition as defined in claim 3 which is capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between said negative electrode and said positive electrode.

13. The lithium secondary battery according to claim 10, wherein said positive electrode comprises lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, lithium vanadium oxide, lithium vanadium phosphate, or a combination thereof.

14. The lithium secondary battery as defined in claim 10 wherein said mixed nano-filament composition further comprises a binder material selected from a polymer, coal tar pitch, petroleum pitch, meso-phase pitch, coke, or a derivative thereof.

15. The lithium secondary battery as defined in claim 10, wherein said mixed nano-filament composition provides a specific capacity of no less than 1,000 mAh per gram of anode material weight.

16. The lithium secondary battery as defined in claim 10, wherein said mixed nano-filament composition provides a specific capacity of no less than 2,000 mAh per gram of anode material weight.

17. The lithium secondary battery as defined in claim 10, wherein said mixed nano-filament composition provides a specific capacity of no less than 3,000 mAh per gram of anode material weight.

18. The lithium secondary battery as defined in claim 11, wherein said mixed nano-filament composition provides a specific capacity of no less than 2,000 mAh per gram of anode material weight.

19. The lithium secondary battery as defined in claim 12, wherein said mixed nano-filament composition provides a specific capacity of no less than 3,000 mAh per gram of anode material weight.

20. A lithium secondary battery comprising a negative electrode, a positive electrode comprising a mixed nano-filament composition as defined in claim 1 which comprises a cathode active filament capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between said negative electrode and said positive electrode.

21. A lithium secondary battery comprising a negative electrode, a positive electrode comprising a mixed nano-filament composition as defined in claim 2 which comprises a cathode active filament capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between said negative electrode and said positive electrode.

22. A lithium secondary battery comprising a negative electrode, a positive electrode comprising a mixed nano-filament composition as defined in claim 3 which comprises a cathode active filament capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between said negative electrode and said positive electrode.

23. A lithium secondary battery of claim 20 wherein said mixed nano-filament composition provides a discharge specific capacity greater than 200 mAh/g, based on per gram of cathode material weight.

24. A lithium secondary battery comprising:

a) a negative electrode comprising a mixed nano-filament composition as defined in claim 1 which comprises an anode active filament capable of absorbing and desorbing lithium ions during charging and recharging of said battery;

b) a positive electrode comprising a mixed nano-filament composition as defined in claim 1 which comprises a cathode active filament capable of desorbing and absorbing lithium ions during charging and recharging of said battery; and

c) a non-aqueous electrolyte disposed between said negative electrode and said positive electrode.