Electrolytic Copper Foil Surface Roughness Control for Graphene Synthesis

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Solution Overview

Problem

Current methods for producing graphene on copper foils face challenges such as surface deformation, non-uniform layer formation, and high resistance due to issues like island-shaped multi-layer growth and amorphous carbon contamination, making it difficult to achieve clean single-layer graphene suitable for industrial mass production.

Innovation Solution

The development of an electrolytic copper foil with specific Rz roughness and thermal treatment conditions, along with controlled plating parameters like TOC and chlorine concentrations, to achieve a graphene resistance of less than 300 ohms per square, ensuring uniform graphene formation and minimizing surface deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional electrolytic copper foil is used for graphene synthesis, then graphene can be formed on the copper foil surface, but surface deformation occurs during thermal treatment leading to non-uniform graphene layers and high resistance

Engineering Contradiction:
Improvesurface uniformityVSAvoidgraphene resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the Rz roughness ratio relationship between M-face and S-face of the copper foil, and by controlling the thermal treatment temperature range (180-220°C) and time range (50-80 minutes) to prevent surface deformation while ensuring uniform graphene formation and low resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by pre-controlling the surface roughness characteristics of the copper foil before graphene synthesis. The M-face and S-face roughness ratio is controlled in advance to prevent surface deformation during subsequent thermal treatment, ensuring uniform graphene layer formation from the outset

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If copper foil with high surface roughness is used to promote graphene nucleation, then graphene formation is facilitated, but surface deformation during thermal treatment increases leading to non-uniform layers

Engineering Contradiction:
Improvegraphene formationVSAvoidlayer uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by optimizing the Rz roughness values to specific ranges (M-face: 0.3-3.0 μm, S-face after treatment: controlled via the ratio relationship) and controlling the thermal treatment parameters (temperature: 180-220°C, time: 50-80 minutes) to balance graphene formation ease with layer uniformity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by differentiating the surface roughness requirements between M-face and S-face of the copper foil. The M-face roughness is controlled to promote graphene nucleation, while the S-face roughness after thermal treatment is controlled to prevent deformation, creating different local surface characteristics for different functional requirements

Inventive Principle:
Principle #3Local quality

3Productivity

If thermal treatment is applied to synthesize graphene on copper foil, then graphene layers are formed, but surface deformation occurs leading to island-shaped multi-layer growth and amorphous carbon contamination

Engineering Contradiction:
Improvegraphene synthesisVSAvoidgraphene cleanliness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the thermal treatment temperature within 180-220°C and time within 50-80 minutes, and by controlling the copper foil surface roughness ratio, to enable efficient graphene synthesis while preventing surface deformation that causes island-shaped growth and amorphous carbon contamination

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies feedback by establishing a specific Rz roughness ratio relationship (0.05≤Rz_M/Rz_S≤0.2) as a control criterion. This feedback mechanism ensures that the copper foil surface characteristics are maintained within optimal ranges to prevent deformation during thermal treatment, thereby ensuring clean single-layer graphene formation

Inventive Principle:
Principle #23Feedback

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 approach effectively blocks surface deformation and achieves uniform graphene synthesis with reduced resistance, facilitating the production of high-quality graphene suitable for industrial applications.

Implementation Method 1

a Rz roughness of a S-face of the electrolytic copper foil after 1 hour treatment at 200° C. in the synthesis of graphene

Methodology Applied
Scientific EffectThermal treatment: Heat Treatment

Implementation Method 2

plating of the copper foil is performed in a copper electrolytic solution under a condition that a total organic carbon (TOC) concentration in the copper electrolytic solution is kept at 3 ppm or lower

Methodology Applied
Scientific EffectElectroplating: Electroplating

Data Source

PatentUS10826117B2Electrolytic copper foil for graphene and method for producing the copper foil
Publication Date: 2020.11.03 ILJIN MATERIALS CO LTD

AI summary

The present disclosure relates to an electrolytic copper foil for graphene and a method for producing the copper foil. More particularly, the present disclosure relates to an electrolytic copper foil for graphene and a method for producing the copper foil, which may facilitate formation of graphene by blocking surface deformation during the electrolytic copper foil formation. In accordance with the present disclosure, the Rz roughness of the S-face of the electrolytic copper foil after 1 hour treatment at 200° C. in the synthesis of graphene on the electrolytic copper foil is defined based on the Relationship 1 below. This may also minimize the deformation of the surface of the electrolytic copper foil at high temperatures:0.05≤(Rz roughness of M-face of electrolytic copper foil/Rz roughness of S-face after treatment at 200° C. for 1 hour)/thickness of electrolytic copper foil≤0.2.  Relationship 1: