Edge-Functionalised Graphene Platelets Balancing Dispersion and Conductivity
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Solution Overview
Problem
Current methods for producing graphene at industrial scales face challenges in achieving high dispersibility and stability in solvents, limiting its use in composite materials and applications due to agglomeration and the need for large solvent quantities.
Innovation Solution
The production of edge-functionalised graphene platelets with partial functionalisation of edges and surfaces, allowing for stable dispersions up to 700 mg/mL in water and improved electrical conductivity, achieved through a method involving suspension in organic nitrile and ester solvents with ruthenium tetroxide oxidation and subsequent washing and drying processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid-phase exfoliation is used to produce graphene, then large quantities can be produced, but large amounts of solvents are required and dispersibility is poor
Solution Approach 1:
The patent applies parameter changes by functionalizing the edges of graphene platelets with oxygen-containing groups (carboxyl, hydroxyl, carbonyl) through oxidation treatment. This chemical modification changes the surface properties of graphene, enabling it to disperse in water at much higher concentrations (up to 10 mg/mL or higher) without requiring large amounts of solvent. The edge functionalization creates hydrophilic groups that improve water compatibility while maintaining the ability to produce large quantities of graphene.
2Reliability
If pure graphene is dispersed in water, then electrical conductivity is maintained, but dispersibility is limited to concentrations below 0.01 g/L
Solution Approach 1:
The patent applies local quality by functionalizing only the edge regions of graphene platelets rather than the entire surface. The edge functionalization with oxygen-containing groups provides hydrophilicity for improved dispersibility, while the large central area of the graphene platelet retains its intrinsic electrical conductivity. This localized modification allows the graphene to achieve both good dispersibility (concentrations up to 10 mg/mL or higher) and maintained electrical conductivity, resolving the contradiction between dispersibility and conductivity.
3Strength
If graphene structures are used in composite materials, then matrix properties can be improved, but homogenous distribution is difficult due to agglomeration
Solution Approach 1:
The patent applies parameter changes through edge functionalization with oxygen-containing groups, which fundamentally alters the surface chemistry of graphene. This modification creates repulsive forces between platelets and improves compatibility with polymer matrices, enabling homogenous distribution at high concentrations (up to 10 mg/mL or higher) without agglomeration. The functionalized graphene can be easily dispersed in polymer matrices, allowing for homogenous composites with improved mechanical and electrical properties.
4Quantity of substance
If edge functionalisation is applied to increase dispersity, then dispersibility improves, but structural integrity of graphene may be compromised
Solution Approach 1:
The patent applies local quality by restricting functionalization to the edge regions of graphene platelets while leaving the large central area intact. This localized approach ensures that the structural integrity and mechanical strength of the graphene backbone are preserved, while the edge functional groups (carboxyl, hydroxyl, carbonyl) provide sufficient hydrophilicity for improved dispersibility (concentrations up to 10 mg/mL or higher). The selective edge modification minimizes structural compromise while achieving the desired dispersibility enhancement.
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
The edge-functionalised graphene platelets provide enhanced dispersibility and conductivity, enabling stable suspensions for extended periods and facilitating the fabrication of composite materials and electrodes with improved properties.
Implementation Method 1
reacting the solution containing suspended graphite or graphene with an oxidant (such as ruthenium tetroxide) to at least partially functionalise edge regions of the graphite or graphene
Implementation Method 2
graphite is exfoliated into graphene in a liquid media, often by use of an ultrasonication. As the layers of graphene are held together by weak van der Waals forces, ultrasonic waves are able to break apart layers of graphene
Implementation Method 3
ultrasonic waves are able to break apart layers of graphite
Implementation Method 4
As the layers of graphene are held together by weak van der Waals forces, ultrasonic waves are able to break apart layers of graphene
Data Source
AI summary
The present disclosure provides a dispersible graphene platelet and a method of making same. The structure of the graphene platelet 10 comprises a base layer 1 of graphene on which at least one discontinuous layer 2, 3, 4 of graphene is stacked, with each layer of graphene above the base layer having a smaller surface area than the layer it is stacked upon. The edges of the base layer and the discontinuous layers stacked upon it are all at least partially functionalised 5, providing a structure with graphene-like properties owing to the base layer and relatively high dispersibility owing to the increased amount of functionalised groups on each platelet. The platelets may be used for a number of applications, for example in the production of electrodes or composite materials.