Method of preparing a nanofiber and a fuel cell including the nanofiber

• US 8,283,091 B2
• Filed: 09/21/2011
• Issued: 10/09/2012
• Est. Priority Date: 01/24/2007
• Status: Expired due to Fees

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Lee, Jeong-hee, Choi, Jae-young, Pak, Chan-ho, Ra, Eun-ju, Lee, Young-hee, An, Kay-hyeok
• Primary Examiner(s): Alejandro, Raymond
• Application Number:
  US13/200,256
• Publication Number:
  US 20120046434A1
• Time in Patent Office: 384 Days
• Field of Search: 429/523, 429/530, 429/533, 429/535, 526/341, 977/948
• US Class Current: 429/523
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: D01F 11/04 of synthetic polymers
• CPC Class Codes: D01F 9/20 from polyaddition, polycondensation or polymerisation products D01F9/145, D01F9/16, D01F9/18 take precedence
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 4/90 Selection of catalytic material
• CPC Class Codes: H01M 4/9083 on carbon or graphite
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• CPC Class Codes: H01M 4/926 on carbon or graphite
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10S 977/948 Energy storage/generating using nanostructure, e.g. fuel cell, battery

Abstract

Provided is a carbon nanofiber, wherein the carbon nanofiber has a surface oxygen content of at least 0.03 calculated by the formula: Oxygen content=[atomic percentage of oxygen/atomic percentage of carbon] using atomic percentages of oxygen and carbon, respectively calculated from an area of an oxygen peak having a binding energy of 524 to 540 eV, an area of a nitrogen peak having a binding energy of 392 to 404 eV, and an area of a carbon peak having a binding energy of 282 to 290 eV in X-ray photoelectron spectroscopy. The nanofibers have high surface oxygen content and may have metal catalyst nano particles densely and uniformly distributed on the outer wall of the carbon nanofibers, thereby having high electrochemical efficiency.

Claims

1. A method of preparing a carbon nanofiber for a fuel cell electrode, the method comprising:

hydrolyzing a surface of a carbon nanofiber precursor with a hydroxide solution having a concentration from 0.05-1 M to form a hydrolyzed carbon nanofiber precursor;

washing the hydrolyzed carbon nanofiber precursor with a hydrochloric acid solution to form a washed carbon nanofiber precursor; and

sintering the washed carbon nanofiber precursor to obtain a carbon nanofiber, and wherein the carbon nanofiber is part of the fuel cell electrode.

2. The method of claim 1, wherein the carbon nanofiber precursor is prepared using an electrospinning method.

3. The method of claim 1, further comprising stabilizing the carbon nanofiber precursor by heat-treatment at a temperature between 200 and 300°

C. under an oxygen-containing atmosphere for 1 to 2 hours prior to the hydrolyzing.

4. The method of claim 1, wherein the carbon nanofiber precursor comprises at least one polymer selected from the group consisting of a polyacrylonitrile-based polymers, acryl-based polymers, pitch-based polymers, and phenol-based polymers.

5. The method of claim 1, wherein the concentration of the hydroxide solution is from 0.05 to 0.5 M.

6. The method of claim 1, wherein the temperature of the hydroxide solution is between 30 and 60°

C.

7. The method of claim 1, wherein the hydrolyzing of the surface of the carbon nanofiber precursor is performed for from 10 minutes to 10 hours.

8. The method of claim 1, wherein the hydroxide solution comprises a hydroxide compound of the formula of MOH, where M is at least one metal selected from the group consisting of Group IA, Group IIA, Group IIIA, Group IVA, Group VA, Group VIA, Group VIIA, Group VIII, Group IB, Group IIB and Group IIIB elements.

9. The method of claim 1, wherein the hydroxide solution is a solution selected from the group consisting of KOH, LiOH, NaOH, and combinations thereof.

10. The method of claim 1, wherein the concentration of the hydrochloric acid solution is from 0.01 to 5 M.

11. The method of claim 1, wherein the sintering is performed in an inert atmosphere and at a temperature between 500 and 1500°

C.