Cross-linked graphene aerogel density control
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Solution Overview
Problem
Current methods for producing cross-linked graphene and graphene oxide networks, such as aerogels and xerogels, lack control over density, shape, conductivity, and internal surface properties, which limits their desirable electrical and mechanical properties for applications like filtration, gas storage, and catalyst support.
Innovation Solution
A method involving the dispersion of graphene or graphene oxide in a solvent, followed by cross-linking using functional groups or linking molecules to form covalently linked gel networks, and subsequent solvent removal to produce aerogels or xerogels with low solvent content, allowing for controlled density and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce cross-linked graphene networks, then the basic structure can be formed, but control over density, shape, conductivity and internal surface is lacking
Solution Approach 1:
The patent applies parameter changes by systematically varying cross-linking density, solvent composition, drying conditions, and functional group types to precisely control the final aerogel properties. By adjusting these parameters during the gelation and drying processes, the invention achieves control over density (0.01-1 g/cm³), surface area (100-1000 m²/g), and electrical conductivity without requiring complex multi-step procedures.
Solution Approach 2:
The patent uses linking molecules as intermediaries to bridge graphene sheets during cross-linking. These intermediaries (such as diamines, diols, or carboxylic acids) enable controlled formation of cross-linked networks while allowing adjustment of network density and topology. The intermediaries facilitate precise control over the gel structure without requiring direct graphene-to-graphene bonding, simplifying the overall process.
2Strength
If high cross-linking density is used to improve mechanical strength, then network robustness increases, but electrical conductivity may decrease due to reduced graphene sheet connectivity
Solution Approach 1:
The patent applies local quality by creating heterogeneous cross-linking densities within the aerogel structure. Regions with higher cross-linking density provide mechanical strength and structural stability, while regions with lower cross-linking density maintain high electrical conductivity through preserved graphene sheet connectivity. This spatial variation in cross-linking density allows simultaneous optimization of both mechanical and electrical properties.
Solution Approach 2:
The patent creates composite structures combining cross-linked graphene networks with residual solvent pockets and unreacted functional groups. This composite approach allows the cross-linked network to provide mechanical strength while the residual components maintain electrical pathways. The composite nature of the material enables both strength and conductivity to coexist through the synergistic combination of different structural elements.
3Stability of the object's composition
If excess reagents are used to ensure complete cross-linking, then reaction completeness improves, but residue removal becomes more difficult and graphene properties are compromised
Solution Approach 1:
The patent employs water-soluble or easily removable linking molecules that can be completely eliminated from the final aerogel structure through simple washing or drying processes. These disposable-like reagents facilitate complete cross-linking during synthesis but do not remain as harmful residues in the final product. The linking molecules are designed to be temporarily present during reaction but easily removed afterward, preventing contamination of the graphene network.
Solution Approach 2:
The patent converts the potential harm of excess reagents into benefit by using functional groups that remain on the graphene surface after cross-linking. These residual functional groups (such as carboxylic acid or hydroxyl groups) can be easily removed or modified through standard purification techniques, and their presence during synthesis actually facilitates complete cross-linking. The potential contamination issue is transformed into a beneficial feature that enables controlled synthesis followed by simple purification.
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 the production of graphene-based aerogels and xerogels with high surface area, robust networks, and improved electrical conductivity, suitable for various industrial applications including filtration, gas storage, and catalyst support, while minimizing the use of excess reagents and preserving graphene properties.
Implementation Method 1
cross-linking said graphene, graphene oxide or a mixture thereof via functional groups present on the graphene and/or the graphene oxide, or with a linking molecule comprising at least two functional sites capable of reacting with the surface of said graphene and/or graphene oxide, to form a covalently cross-linked gel network
Implementation Method 2
removing said solvent to produce a cross-linked aerogel or xerogel with a solvent content of less than 10%
Data Source
AI summary
The present invention relates to a method for the production of cross-linked graphene and graphene oxide networks, which are selected from aerogels and xerogels with improved performance and characteristics thereof. The invention is also concerned with graphene and graphene oxide networks, which are selected from aerogels and xerogels produced by such processes and uses thereof.