Graphene Sheets via Electrochemical Exfoliation

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Solution Overview

Problem

Current methods for producing high-quality graphene sheets are either unsuitable for large-scale production or are costly, with existing mass production methods often resulting in low electric conductivity and small sizes.

Innovation Solution

A cost-effective electrochemical exfoliation method involving electrodes immersed in a solution with an electrolyte, such as acids, anionic surfactants, or salts, to produce high-quality graphene sheets on a large scale, which can be further processed to enhance conductivity and transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical exfoliation is used to produce high-quality graphene sheets, then the quality of graphene sheets is improved, but the scalability and production cost are worsened

Engineering Contradiction:

Improvequality of graphene sheetsVSAvoidscalability of production

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces mechanical exfoliation methods with electrochemical exfoliation. A constant potential is applied between two electrodes immersed in an electrolyte solution, causing exfoliation of graphite into graphene sheets through electrochemical reactions rather than mechanical force. This substitution enables large-scale production while maintaining high sheet quality and electrical conductivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If chemical vapor deposition is used for mass production of graphene sheets, then the production scale is improved, but the cost and quality (electric conductivity) are worsened

Engineering Contradiction:

Improveproduction scaleVSAvoidelectric conductivity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs electrochemical exfoliation where a constant potential (e.g., 0.1-250 V) is applied between electrodes in an electrolyte solution. By controlling electrical parameters and solution composition, the method achieves both scalable production and high electrical conductivity in the produced graphene sheets, avoiding the limitations of chemical vapor deposition.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If chemical exfoliation is used to produce graphene sheets, then the production scale is improved, but the quality (size and electric conductivity) is worsened

Engineering Contradiction:

Improveproduction scaleVSAvoidsize and electric conductivity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent substitutes chemical exfoliation with electrochemical exfoliation. By applying a constant potential between electrodes in an electrolyte solution, the method achieves large-scale production of graphene sheets with improved size and electrical conductivity, overcoming the drawbacks of conventional chemical exfoliation methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables fast, scalable, high-yield production of high-quality graphene sheets with ultra-transparency and low resistance, potentially replacing expensive indium tin oxide electrodes.

Implementation Method 1

immersing, in a solution containing an electrolyte, a portion of a first electrode and a portion of a second electrode

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

a cost-effective electrochemical exfoliation of a carbon material produces high-quality graphene sheets on a large scale

Methodology Applied

Scientific EffectElectrochemical exfoliation:

Data Source

PatentUS8858776B2Preparation of graphene sheets

Publication Date: 2014.10.14 ACAD SINICA

AI summary

A method of preparing graphene sheets. The method includes: immersing a portion of a first electrode and a portion of a second electrode in a solution containing an acid, an anionic surfactant, a salt, an oxidizing agent, or any combination thereof as an electrolyte, the immersed portion of the first electrode including a first carbon material and the immersed portion of the second electrode including a second carbon material or a metal; causing a potential to exist between the first and second electrodes; and recovering, from the solution, graphene sheets exfoliated from the carbon material(s). Also disclosed is a method of preparing a graphene film electrode. The method includes: dissolving graphene sheets in an organic solvent to form a solution, applying the solution on a substrate, adding deionized water to the solution on the substrate so that a graphene film is formed, and drying the graphene film.