Vertically-aligned graphene-carbon fiber hybrid electrodes and methods for making same

Patent metadata

Field	Value
Publication number	US-2021147999-A1
Application number	US-202016951150-A
Country	US
Kind code	A1
Filing date	Nov 18, 2020
Priority date	Nov 19, 2019
Publication date	May 20, 2021
Grant date	—

Abstract

Graphene electrodes-based supercapacitors are in demand due to superior electrochemical characteristics. However, commercial applications have been limited by inferior electrode cycle life. A method to fabricate highly efficient supercapacitor electrodes using pristine graphene sheets vertically-stacked and electrically connected to the carbon fibers which results in vertically-aligned graphene-carbon fiber nanostructure is disclosed. The vertically-aligned graphene-carbon fiber electrode prepared by electrophoretic deposition possesses a mesoporous three-dimensional architecture which enabled faster and efficient electrolyte-ion diffusion with a specific capacitance of 333.3 F g −1 . The electrodes have electrochemical cycling stability of more than 100,000 cycles with 100% capacitance retention. Apart from the electrochemical double layer charge storage, the oxygen-containing surface moieties and α-Ni(OH) 2 present on the graphene sheets enhance the charge storage by faradaic reactions. This enables the assembled device to provide a gravimetric energy density of 76 W h kg −1 with a 100% capacitance retention even after 1,000 bending cycles.

First claim

What is claimed is:

1 . A method of making a hybrid material comprising vertically-aligned graphene stacks on a carbon fiber, the method comprising:
electrophoretically depositing graphene on a carbon fiber substrate to thereby fabricate the composite material.

2 . The method of claim 1 , further comprising:
placing a working electrode comprising the carbon fiber substrate in a metallic salt solution, the metallic salt solution having graphene disbursed therein; electrically connecting the working electrode to a counter electrode; and applying a voltage to the working electrode to thereby electrophoretically deposit the graphene on the carbon fiber substrate.

3 . The method of claim 2 , wherein the metallic salt solution is a Nickel solution.

4 . The method of claim 3 , wherein the Nickel solution is a Nickel nitrate solution.

5 . The method of claim 3 , wherein the metallic salt solution is dissolved in a solvent.

6 . The method of claim 5 , wherein the solvent is an alcohol-based solvent.

7 . The method of claim 2 , wherein the graphene is mixed into the metallic salt solution.

8 . The method of claim 7 , wherein ultrasonication is used to mix the graphene into the metallic salt solution.

9 . The method of claim 1 , further comprising drying the graphene deposited on the carbon fiber.

10 . The method of claim 9 , wherein the drying comprises drying in an oven.

11 . A hybrid electrode comprising:
a substrate comprising carbon fibers; and graphene sheets vertically stacked on and electrically connected to the carbon fibers, wherein the hybrid electrode has about 100% capacitance retention after at least 100,000 cycles.

12 . The hybrid electrode of claim 11 , wherein the hybrid electrode has about 100% capacitance retention after at least 1,000 bending cycles.

13 . The hybrid electrode of claim 11 , wherein the carbon fibers have an average diameter of around 6 μm.

14 . The hybrid electrode of claim 11 , wherein the hybrid electrode has mesoporous nanostructure.

Assignees

• Univ Central Florida Res Found Inc

Inventors

• Thomas Jayan
• Cherusseri Jayesh
• Kumar Kowsik Sambath

Classifications

• H01G11/40

  Fibres · CPC title

• H01G11/32

  Carbon-based · CPC title

• Y02E60/13

  Energy storage using capacitors · CPC title

• C25D3/12

  of nickel or cobalt · CPC title

• C25D5/54

  Electroplating of non-metallic surfaces (C25D7/12 takes precedence) · CPC title