Graphene Matrix Composite Thermal Management
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Solution Overview
Problem
Current graphitic materials for heat dissipation, such as flexible graphite foils and carbon nano-tube papers, suffer from low thermal conductivity, mechanical weakness, and the tendency to flake off, leading to internal shorting and structural integrity issues in electronic devices.
Innovation Solution
A graphene oxide gel-derived unitary graphene matrix composite with closely packed, chemically bonded graphene planes and a carbon or graphite filler phase, which is produced through a process that aligns graphene planes parallel to each other and chemically bonds them, enhancing thermal and electrical conductivity, mechanical strength, and scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If flexible graphite foils or carbon nano-tube papers are used for heat dissipation, then thermal conductivity is improved, but mechanical strength and structural integrity deteriorate due to flaking and weakness
Solution Approach 1:
The patent employs a composite material structure consisting of carbon nanotubes dispersed within a graphene matrix. The graphene planes form a continuous, chemically bonded network that provides structural integrity and prevents flaking, while the carbon nanotubes contribute to thermal conductivity. This composite approach allows simultaneous achievement of high thermal performance and mechanical strength by combining the advantages of both carbon nanotubes and graphene in a unified structure.
2Temperature
If conventional graphitic materials are used, then thermal conductivity is enhanced, but reliability deteriorates due to flaking off and internal shorting
Solution Approach 1:
The graphene matrix composite structure prevents flaking by creating a continuous, chemically bonded network of graphene planes that are integrated with the carbon nanotube filler. This unified composite structure eliminates the delamination and particle detachment issues found in conventional layered graphitic materials, thereby preventing internal shorting and improving device reliability while maintaining thermal conductivity.
Solution Approach 2:
The patent creates a heterogeneous structure where carbon nanotubes are locally distributed within the graphene matrix, allowing different regions to perform specialized functions. The graphene planes provide structural continuity and electrical connectivity, while the carbon nanotube regions enhance thermal conduction pathways. This local differentiation of material properties within the composite enables simultaneous optimization of reliability and thermal performance.
3Ease of manufacture
If graphite particles with multiple grains are used, then availability is improved, but thermal conductivity deteriorates due to grain boundaries and misorientation
Solution Approach 1:
The patent uses naturally available graphite particles as starting material and segments them into individual graphene planes through exfoliation. These separated graphene planes are then reassembled into a new composite structure where they are chemically bonded in a controlled orientation, eliminating the grain boundary problems of conventional multi-grain graphite while maintaining ease of manufacture from common graphite sources.
Solution Approach 2:
The patent fundamentally changes the structural parameters of graphite by transforming multi-grain particles into a composite where graphene planes are chemically bonded with controlled orientation and spacing. The inter-graphene spacing is reduced and oriented parallel to each other, and chemical bonding between planes eliminates grain boundary thermal resistance, thereby dramatically improving thermal conductivity while starting from readily available graphite material.
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 unitary graphene matrix composite achieves thermal conductivity greater than 600 W/mK, electrical conductivity greater than 2000 S/cm, and tensile strength greater than 80 MPa, while eliminating the flaking issue, making it suitable for advanced thermal management applications in electronic devices.
Implementation Method 1
which unitary graphene matrix is obtained from heat-treating a graphene oxide gel at a temperature higher than 100° C.
Implementation Method 2
closely packed and chemically bonded graphene planes having an inter-graphene plane spacing of 0.335 to 0.40 nm
Implementation Method 3
the carbon or graphite filler phase is in a particulate, filamentary, or rod-like form dispersed in the unitary graphene matrix
Implementation Method 4
The unitary graphene matrix composite achieves thermal conductivity greater than 600 W/mK
Implementation Method 5
electrical conductivity greater than 2000 S/cm
Data Source
AI summary
A process for producing a unitary graphene matrix composite, the process comprising: (a) preparing a graphene oxide gel having graphene oxide molecules dispersed in a fluid medium, wherein the graphene oxide gel is optically transparent or translucent; (b) mixing a carbon or graphite filler phase in said graphene oxide gel to form a slurry; (c) dispensing said slurry onto a surface of a supporting substrate or a cavity of a molding tool; (d) partially or completely removing the fluid medium from the slurry to form a composite precursor; and (e) heat-treating the composite precursor to form the unitary graphene composite at a temperature higher than 100° C. This composite exhibits a combination of exceptional thermal conductivity, electrical conductivity, mechanical strength, surface hardness, and scratch resistance.