PROCESS FOR PREPARING A SILICON-CARBON NANOCOMPOSITE NANOFIBER

• US 20170191193A1
• Filed: 03/20/2017
• Published: 07/06/2017
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Cornell University
• Original Assignee: Cornell University
• Inventors: Joo, Yong Lak, Kim, Kyoung Woo, Kim, Yong Seok
• Granted Patent: US 10,450,674 B2
• Time in Patent Office: Days
• CPC Class Codes: D01D 1/02 Preparation of spinning solutions
• CPC Class Codes: D01D 5/0015 characterised by the initial state of the material
• CPC Class Codes: D01D 5/003 the material being a polymer solution or dispersion D01D5/0053 takes precedence
• CPC Class Codes: D01D 5/0069 characterised by the spinning section, e.g. capillary tube, protrusion or pin
• CPC Class Codes: D01F 1/02 Addition of substances to the spinning solution or to the melt addition of substances to viscose D01F2/08
• CPC Class Codes: D01F 9/12 Carbon filaments; Apparatus specially adapted for the manufacture thereof
• CPC Class Codes: D01F 9/20 from polyaddition, polycondensation or polymerisation products D01F9/145, D01F9/16, D01F9/18 take precedence
• CPC Class Codes: D01F 9/328 for manufacturing filaments from polyaddition, polycondensation, or polymerisation products
• CPC Class Codes: D04H 1/728 by electro-spinning electro-spinning methods and apparatus D01D5/0007
• 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

Abstract

Provided herein are nanofibers comprising carbon precursors, nanofibers comprising carbon matrices, and processes for preparing the same. In specific examples, provided herein are high performance lithium ion battery anodic nanofibers comprising non-aggregated silicon domains in a continuous carbon matrix.

Claims

1. A process for preparing a silicon-carbon nanocomposite nanofiber, the process comprising:

a. providing an aqueous fluid stock comprising polyvinylalcohol, a plurality of silicon nanoparticles having an average diameter of less than 100 nm, and a nanostructured carbon having an aspect ratio of at least 5, the weight-to-weight ratio of silicon nanoparticles to polyvinylalcohol being at least 1;

10, and the weight-to-weight ratio of nanostructured carbon to polyvinylalcohol being at least 1;

10;

b. electrospinning the fluid stock, producing a nanofiber comprising the polyvinylalcohol, the silicon nanoparticles, and the nanostructured carbon, the electrospinning being gas assisted; and

c. thermally carbonizing the polyvinylalcohol of the nanofiber, thereby producing the silicon-carbon nanocomposite nanofiber,

the silicon-carbon nanocomposite nanofiber comprising at least 60 elemental wt. % silicon and 5 wt. % to 25 wt. % carbon.

2. The process of claim 1, wherein the silicon-carbon nanocomposite nanofiber comprises at least 75 elemental wt. % silicon.

3. The process of claim 1, wherein thermally treating comprises heating to a temperature between 400°

C. and 2000°

C.

4. The process of claim 1, wherein the thermal treatment carbonizes the polyvinylalcohol.

5. The process of claim 1, wherein the thermal treatment is performed under inert or reducing conditions.

6. The process of claim 1, wherein the electrospinning is coaxially gas-assisted.

7. A process for preparing a composite nanofiber, the process comprising:

a. providing a fluid stock comprising a polymer and a nanostructured carbon, the fluid stock comprising a weigh-to-weight ratio of nanostructured carbon to polymer of at least 1;

10; and

b. electrospinning the fluid stock, producing a nanofiber comprising the polymer, and the nanostructured carbon, the electrospinning being gas assisted.

8. The process of claim 7, wherein the fluid stock comprises the nanostructured carbon and the polymer in a nanostructured carbon-to-polymer weight-to-weight ratio of 1:

4 to 4;

1.

9. The process of claim 7, wherein the fluid stock further comprises a plurality of silicon nanoparticles.

10. The process of claim 9, wherein the plurality of silicon nanoparticles has an average diameter of less than 100 nm.

11. The process of claim 7, wherein the fluid stock comprises the silicon nanoparticles and the polymer in a silicon nanoparticles-to-polymer weight-to-weight ratio of at least 1:

10.

12. The process of claim 7, further comprising thermally treating the nanofiber, thereby producing the carbon composite nanofiber.

13. The process of claim 7, further comprising washing the nanofiber prior to thermal treatment.

14. The process of claim 7, wherein the electrospinning is coaxially gas-assisted.

15. The process of claim 7, wherein the nanostructured carbon comprises carbon black, a graphene, carbon nanotubes, or a combination thereof.

16. The process of claim 7, wherein the nanostructured carbon comprises high aspect ratio nanostructured carbon, the aspect ratio thereof being at least 10.

17. The process of claim 7, wherein the polymer is polyvinyl alcohol (PVA), polyethylene oxide (PEO), or polyacrylonitrile (PAN).

18. The process of claim 7, wherein the polymer is present in the fluid stock in a concentration of at least 2 wt. %.

19. The process of claim 18, wherein the polymer is present in the fluid stock in a concentration of at least 5 wt. %.

20. The process of claim 19, wherein the polymer is present in the fluid stock in a concentration of at least 10 wt. %.