Continuous Graphitic Fiber Fabric via Shear-Aligned GO
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Solution Overview
Problem
The production of continuous graphite fibers is a complex, energy-intensive, and costly process, and existing methods fail to produce fibers with high tensile strength, thermal conductivity, and electrical conductivity due to defects and porosity in the material structure.
Innovation Solution
A process involving the use of living graphene oxide gel, where graphene oxide molecules are aligned and chemically bonded to form continuous graphitic fibers with minimal defects and high conductivity, using mechanical stress-induced molecular alignment and heat treatment to achieve parallel graphene planes and low porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional carbonization and graphitization processes are used to produce continuous graphite fibers, then the fibers can be manufactured, but the process is energy-intensive, complex, and costly with defects and porosity in the material structure
Solution Approach 1:
The invention applies preliminary action by pre-aligning graphene oxide sheets in an aqueous suspension before fiber formation. The sheets are oriented parallel to each other using shear forces during extrusion, and this preliminary alignment is maintained through the drying and heat treatment processes, avoiding the need for complex post-processing steps to achieve structural order.
Solution Approach 2:
The invention extracts the essential requirement for fiber structure by directly forming aligned graphene oxide sheets into continuous fibers during extrusion, rather than attempting to reorganize randomly arranged sheets after fiber formation. This extraction of the alignment step from post-processing to during-processing simplifies the overall process.
2Strength
If conventional carbonization processes are used, then continuous carbon fibers can be produced, but the fibers exhibit defects and porosity that reduce tensile strength, thermal conductivity, and electrical conductivity
Solution Approach 1:
The invention changes the fundamental parameter of fiber composition from carbonized polymers (PAN, pitch) to directly assembled graphene oxide sheets. This parameter change allows for continuous, defect-free structures with superior mechanical and electrical properties, as the sheets are aligned and bonded during formation rather than through subsequent heat treatment of disordered structures.
Solution Approach 2:
The invention uses composite materials by combining multiple graphene oxide sheets into a continuous fiber structure with intimate contact and strong bonding between sheets. The aligned sheet structure creates a composite material with enhanced tensile strength and electrical conductivity compared to conventional carbon fibers with their inherent defects and porosity.
3Strength
If high temperature graphitization (2500-3000°C) is applied to increase Young's modulus, then higher modulus is achieved, but the process becomes more energy-intensive and time-consuming
Solution Approach 1:
The invention applies preliminary action by pre-aligning graphene oxide sheets in an aqueous suspension before fiber formation. The sheets are oriented parallel to each other using shear forces during extrusion, and this preliminary alignment is maintained through the drying and heat treatment processes, avoiding the need for complex post-processing steps to achieve structural order.
Solution Approach 2:
The invention changes the fundamental parameter of fiber composition from carbonized polymers (PAN, pitch) to directly assembled graphene oxide sheets. This parameter change allows for continuous, defect-free structures with superior mechanical and electrical properties, as the sheets are aligned and bonded during formation rather than through subsequent heat treatment of disordered structures.
4Ease of manufacture
If conventional carbon fiber production methods are used, then fibers can be manufactured from PAN or pitch, but the process requires extreme temperature control and atmospheric control making it challenging and expensive
Solution Approach 1:
The invention replaces the thermal-mechanical system of conventional carbonization (heating to 2000-3000°C with controlled atmosphere) with a mechanical assembly process. Graphene oxide sheets are aligned and assembled into fibers using shear forces and extrusion at ambient or mild temperatures, eliminating the need for extreme temperature and atmospheric control.
Solution Approach 2:
The invention uses water as an intermediary medium to facilitate the assembly of graphene oxide sheets into fibers. The aqueous suspension allows sheets to be manipulated, aligned, and extruded under mild conditions, replacing the need for high-temperature processing atmospheres used in conventional carbon fiber production.
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 resulting fibers exhibit exceptional thermal conductivity, electrical conductivity, tensile strength, and Young's modulus, surpassing previous continuous graphitic fibers, with a porosity level less than 10% and a high packing factor, enabling their use in advanced composite materials and applications.
Implementation Method 1
mechanical stress-induced molecular alignment
Implementation Method 2
chemically bonded to form continuous graphitic fibers
Implementation Method 3
heat treatment to achieve parallel graphene planes and low porosity
Implementation Method 4
heat treating the continuous graphene oxide fiber to form the continuous graphitic fiber
Data Source
AI summary
Multi-functional and high-performing fabric comprising a first layer of yarns woven to form the fabric wherein the yarns comprise at least one unitary graphene-based continuous graphitic fiber comprising at least 90% by weight of graphene planes that are chemically bonded with one another having an inter-planar spacing d002 from 0.3354 nm to 0.4 nm as determined by X-ray diffraction and an oxygen content less than 5% by weight. A majority of the graphene planes in such a continuous graphitic fiber are parallel to one another and parallel to a fiber axis direction. The graphitic fiber contains no core-shell structure, has no helically arranged graphene domains or domain boundaries, and has a porosity level less than 5% by volume, more typically less than 2%, and most typically less than 1% (practically pore-free).