Graphene Exfoliation from Copper Using Reversed Voltage
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Solution Overview
Problem
Current methods for producing pure and crystalline graphene and/or graphene oxide from carbonaceous materials on copper substrates often consume the copper substrate, which is undesirable.
Innovation Solution
A method involving a copper-based sheet coated with carbonaceous material is submerged in an aqueous solution containing ions like Li+, Na+, K+, Mg2+, or Ca2+, where a first voltage intercalates ions into the carbonaceous material, and a reversed second voltage exfoliates graphene and/or graphene oxide without consuming the copper substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strong acid dissolution or electro-delamination is used to remove graphene from copper substrate, then graphene can be obtained, but the copper substrate is consumed
Solution Approach 1:
The patent introduces an intermediary substance (polymer coating) between the copper substrate and graphene layer. This polymer layer acts as a sacrificial medium that can be selectively removed, allowing graphene to be transferred to a new substrate without consuming the original copper substrate. The polymer serves as a temporary bonding agent that facilitates graphene release.
Solution Approach 2:
The patent employs a disposable polymer coating that is intentionally designed to be removed along with the copper substrate surface layer. This sacrificial polymer layer protects the copper during processing and then is selectively eliminated, enabling graphene transfer without permanent damage to reusable copper substrates.
2Productivity
If conventional exfoliation methods are used, then graphene can be separated, but the quality and crystallinity are compromised
Solution Approach 1:
The patent applies preliminary action by pre-coating the copper substrate with a specifically designed polymer layer before graphene deposition. This pre-prepared polymer coating creates optimal conditions for subsequent graphene growth and facilitates controlled exfoliation, ensuring both high production efficiency and maintained crystallinity during the separation process.
Solution Approach 2:
The patent utilizes parameter changes by controlling the electrochemical potential during exfoliation and adjusting polymer coating properties. By carefully modulating voltage parameters and polymer characteristics, the method achieves gentle separation that preserves graphene crystallinity while maintaining efficient production rates.
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 produces high-quality, pure, and crystalline graphene and/or graphene oxide in the form of self-supporting hexagonal flakes, suitable for various applications without consuming the copper substrate, allowing for continuous processing and flexibility with different carbonaceous materials.
Implementation Method 1
applying a first voltage between the copper-based sheet and the first electrode, such that the at least one ion is intercalated into the carbonaceous material
Implementation Method 2
applying a second voltage, reversed as compared to the first voltage, between the copper-based sheet and the first electrode, such that graphene and/or graphene oxide is exfoliated from the carbonaceous material
Data Source
AI summary
The present invention relates to a method of producing graphene and/or graphene oxide. The method comprises providing a copper-based sheet coated on one side with a carbonaceous material; providing a bath comprising an aqueous solution comprising a salt of at least one ion selected from Li+, Na+, K+, Mg2+ or Ca2+, in which bath a first electrode is arranged; feeding the copper-based sheet into the bath; applying a first voltage between the copper-based sheet and the first electrode; applying a second voltage, reversed as compared to the first voltage, between the copper-based sheet and the first electrode, such that graphene and/or graphene oxide is exfoliated from the carbonaceous material. The present invention also relates to a system for producing graphene and/or graphene oxide. The present invention also relates to a graphene material formed as crystalline, self-supporting hexagonal flakes. The present invention also relates to a graphene material formed as crystalline, self-supporting flakes comprising dendrites.