Hybrid nano-filament anode compositions for lithium ion batteries

Patent metadata

Field	Value
Publication number	US-9564629-B2
Application number	US-620908-A
Country	US
Kind code	B2
Filing date	Jan 2, 2008
Priority date	Jan 2, 2008
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

This invention provides a hybrid 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 comprising substantially interconnected pores, wherein the filaments have an elongate dimension and a first transverse dimension with the first transverse dimension being less than 500 nm (preferably less than 100 nm) and an aspect ratio of the elongate dimension to the first transverse dimension greater than 10; and (b) micron- or nanometer-scaled coating that is deposited on a surface of the filaments, wherein the coating comprises an anode active material capable of absorbing and desorbing lithium ions and the coating has a thickness less than 20 μm (preferably less than 1 μm). Also provided is a lithium ion battery comprising such an electrode as an anode. The battery exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

First claim

The invention claimed is:

1. A lithium secondary battery comprising a positive electrode, a negative electrode comprising a hybrid nano-filament composition which is capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between said negative electrode and said positive electrode, wherein said hybrid nano-filament composition comprises:
a) An aggregate of nanometer-scaled, electrically conductive carbon filaments that are interconnected, intersected, or percolated to form a porous, electrically conductive filament network comprising interconnected pores for accommodating said non-aqueous electrolyte, wherein said nanometer-scaled, electrically conductive carbon filaments have an elongate dimension and a first transverse dimension, which is a diameter or a thickness, said first transverse dimension being less than 500 nm and an aspect ratio of said elongate dimension to said first transverse dimension greater than 10, and wherein said nanometer-scaled, electrically conductive carbon filaments are carbonized electro-spun fibers; and
b) Micron- or nanometer-scaled coating that is deposited on a surface of said nanometer-scaled, electrically conductive carbon filaments, wherein said coating deposited on said nanometer-scaled, electrically conductive carbon filaments comprises an negative active material capable of absorbing and desorbing lithium ions and said coating has a thickness less than 20 μm;
wherein said nanometer-scaled, electrically conductive carbon filaments enable said deposited coating to freely undergo strain relaxation in transverse directions so that said coating does not lose contact with said nanometer-scaled, electrically conductive carbon filaments during charge/discharge cycles of the lithium secondary battery, wherein said coating is wrapped around said nanometer-scaled, electrically conductive carbon filament, wherein said coating deposited on said nanometer-scaled, electrically conductive carbon filaments comprises said negative active material selected from the group consisting of:
i. germanium (Ge), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), and cadmium (Cd);
ii. alloys or intermetallic compounds of Ge, Sb, Bi, Zn, Al, or Cd with other elements, wherein said alloys or compounds are stoichiometric or non-stoichiometric;
iii. oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Ge, Sb, Bi, Zn, Al, I or Cd, and their mixtures or composites; and
iv. combinations thereof.

2. The lithium secondary battery of claim 1 wherein said nanometer-scaled, electrically conductive carbon filaments have a transverse dimension smaller than 100 nm or said coating has a thickness smaller than 1 μm.

3. The lithium secondary battery of claim 1 wherein said coating has a thickness smaller than 200 nm.

4. The lithium secondary battery of claim 1 wherein said nanometer-scaled, electrically conductive carbon filaments comprise an electrically conductive, electro-spun polymer fiber, electro-spun polymer nanocomposite fiber comprising a conductive filler, nano carbon fiber obtained from carbonization of an electro-spun polymer fiber, electro-spun pitch fiber, or a combination thereof.

5. The lithium secondary battery as defined in claim 1 wherein the coating comprises Ge as a primary element with a Ge content no less than 50% by weight based on the total weight of the coating.

6. The lithium secondary battery as defined in claim 2 wherein the coating comprises Ge as a primary element with Ge content no less than 50% by weight based on the total weight of the coating.

7. The lithium secondary battery as defined in claim 1 wherein the coating comprises an element selected from Ge, Cd, Sb, Bi, Zn, or a combination thereof.

8. The lithium secondary battery according to claim 1 , wherein said positive electrode comprises lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, lithium vanadium phosphate, or a combination thereof.

9. The lithium secondary battery as defined in claim 1 , wherein said hybrid 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.

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

11. The lithium secondary battery as defined in claim 1 , wherein said hybrid nano-filament composition provides a specific capacity of no less than 2,000 mAh per gram of the anode composition.

12. The lithium secondary battery as defined in claim 1 , wherein said hybrid nano-filament composition provides a specific capacity of no less than 3,000 mAh per gram of the anode composition.

13. An electrochemical cell electrode comprising a hybrid nano-filament composition, said hybrid nano-filament composition comprising:
a) an aggregate of nanometer-scaled, electrically conductive graphene platelets that are interconnected, intersected, or percolated to form a porous, electrically conductive graphene platelets network comprising interconnected pores, wherein said nanometer-scaled, electrically conductive graphene platelet has a length and a thickness, said thickness being no greater than 100 nm, and a length-to-thickness aspect ratio no less than 10; and
b) micron- or nanometer-scaled coating that is deposited on a surface of said nanometer-scaled, electrically conductive graphene platelets, wherein said coating deposited on said nanometer-scaled, electrically conductive graphene platelets comprises an anode active material selected from the group consisting of:
i. germanium (Ge), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), and cadmium (Cd);
ii. alloys or intermetallic compounds of Ge, Sb, Bi, Zn, Al, or Cd with other elements, wherein said alloys or compounds are stoichiometric or non-stoichiometric;
iii. oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Ge, Sb, Bi, Zn, Al, or Cd, and their mixtures or composites; and
iv. combinations thereof;

wherein said nanometer-scaled, electrically conductive graphene platelets enable said deposited coating to freely undergo strain relaxation in transverse directions so that said coating does not lose contact with said nanometer-scaled, electrically conductive graphene platelets during charge/discharge cycles of the electrochemical cell, wherein said coating is wrapped around said nanometer-scaled, electrically conductive graphene platelet.

Assignees

• Zhamu Aruna
• Jang Bor Z
• Nanotek Instruments Inc

Inventors

• Zhamu Aruna
• Jang Bor Z

Classifications

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• D04H3/16

  with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion · CPC title

• D06M11/485

  Oxides or hydroxides of manganese; Manganates (permanganates D06M11/50) · CPC title

• H01M4/139 Primary

  Processes of manufacture · CPC title

• D04H3/02

  characterised by the method of forming fleeces or layers, e.g. reorientation of yarns or filaments · CPC title