Edge-Functionalized Graphene Platelets Against Agglomeration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing graphene at industrial scales face challenges in achieving high dispersibility and stability in solvents, leading to agglomeration and limited concentration usage, which hinders its application in composite materials and storage.
Innovation Solution
Edge-functionalized graphene platelets are produced using ruthenium oxide to partially oxidize the edges, allowing for stable dispersions in water up to 10 mg/mL for months and in organic solvents up to 50 mg/mL for hours, with further functionalization by metal ions for enhanced properties.
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 modifying the chemical composition of graphene through edge functionalization with carboxylic acid groups. This chemical modification changes the interaction parameters between graphene sheets and solvent molecules, enabling stable dispersion at high concentrations (up to 10 mg/mL in water and 50 mg/mL in organic solvents) without requiring large amounts of solvent. The functionalization transforms the surface chemistry parameters of graphene, resolving the contradiction between production quantity and solvent requirement.
2Quantity of substance
If graphene is dispersed at high concentrations, then storage is feasible, but graphene tends to agglomerate and restack
Solution Approach 1:
The patent modifies the chemical parameters of graphene by introducing carboxylic acid functional groups at the edges through oxidation treatment. This changes the surface energy and interfacial interaction parameters, preventing agglomeration and restacking even at high concentrations. The functionalized edges create steric and electrostatic repulsion barriers, maintaining dispersion stability at concentrations up to 10 mg/mL in water and 50 mg/mL in organic solvents for extended periods.
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-functionalized graphene platelets achieve high dispersibility and stability, enabling concentrations up to 700 mg/mL in water and 350-700 mg/mL in organic solvents, with improved electrical conductivity and suitability for composite materials and electrochemical processes.
Implementation Method 1
edge regions of the base layer and discontinuous layers are at least partially functionalised by oxidation with ruthenium oxide
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
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
Figure 1
Figure 2~3
Figure 4
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.