Continuous Graphene Synthesis Using Cross-Direction Joule Heating
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Solution Overview
Problem
Existing methods for graphene production face challenges in industrial scalability due to cost inefficiencies from quartz tube degradation, metal electrode contamination, and the need for batch processing, which hinder continuous production.
Innovation Solution
A device and method for continuous graphene synthesis using electrodes made from materials like copper, brass, stainless steel, and graphite, with independent movement and electrical current directions, allowing for continuous processing and reducing contamination, and incorporating quartz walls for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If quartz tubes are used for joule heating, then the carbon source can be heated to high temperatures, but the quartz tubes are degraded and contaminated during the process, requiring disposal after single use which increases production costs
Solution Approach 1:
The patent removes the quartz tube from the system entirely, replacing it with a graphite electrode that serves both as the heating element and the container wall. This extraction of the quartz tube eliminates the degradation and contamination issues while maintaining the high temperature heating capability through the graphite electrode's superior thermal stability.
Solution Approach 2:
The patent uses graphite as a composite material that combines the functions of the heating element and the container wall. Graphite's high thermal stability and electrical conductivity allow it to withstand the extreme temperatures and electrical stresses without degrading, eliminating the need for separate quartz tubes.
2Power
If metal electrodes such as copper and brass are used, then electrical current can be applied to heat the carbon source, but metal contaminants are added to the graphene powder which affects product purity
Solution Approach 1:
The patent employs graphite electrodes that can be easily replaced and are inherently resistant to contamination. While graphite is consumable, its chemical inertness towards carbon and its ability to be replaced without affecting product purity makes it a superior choice compared to metal electrodes that introduce harmful contaminants.
Solution Approach 2:
The patent uses graphite electrodes that are chemically homogeneous with the carbon source material. This homogeneity ensures that no foreign metal contaminants are introduced during the heating process, as the graphite reacts with or mixes with the carbon source without introducing impurities, thereby maintaining graphene powder purity.
3Ease of operation
If batch processing is used, then the device can be operated with simple assembly and disassembly, but large scale continuous production is prevented which reduces productivity
Solution Approach 1:
The patent introduces a dynamic feeding mechanism that allows continuous introduction of carbon source material into the heating zone. The electrode assembly can be dynamically adjusted and repositioned, enabling continuous operation without requiring complete disassembly and reassembly between batches, thus transitioning from batch to continuous processing mode.
Solution Approach 2:
The patent enables continuous useful action by maintaining the heating process without interruption. The graphite electrode's durability and the dynamic feeding mechanism allow carbon source material to be continuously fed through the heating zone, eliminating the stop-start nature of batch processing and achieving continuous graphene production.
4Power
If copper wool is used as electrode, then electrical current can be applied for heating, but the copper wool is degraded by the process which further increases production costs
Solution Approach 1:
The patent replaces copper wool with graphite electrodes that have superior thermal and electrical stability. While graphite is also consumable, its resistance to degradation at high temperatures and its chemical inertness give it a significantly longer operational lifespan, reducing the frequency of replacement and lowering overall production costs.
Solution Approach 2:
The patent changes the material parameter of the electrode from copper-based to graphite-based. This parameter change fundamentally alters the electrode's resistance to thermal and chemical degradation, enabling it to maintain its structural and functional integrity at the extreme temperatures required for graphene synthesis, thereby extending its service life.
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
Enables low-cost, continuous production of graphene by minimizing quartz and metal contamination, increasing batch sizes, and reducing process time, thereby enhancing industrial scalability.
Implementation Method 1
The device includes at least two electrodes for applying an electrical current through the space for joule heating the carbon source
Data Source
AI summary
Provided herein is a method and a device for continuous synthesis of graphene. The device includes a container having a space for holding a carbon source, wherein the container has an entry opening for receiving the carbon source material, at least two electrodes for applying an electrical current through the space for joule heating the carbon source, wherein the space for joule heating the carbon source is between the at least to electrodes, and a movement component for moving the carbon source, with respect to the container, into the entry opening in a first direction and the at least two electrodes apply the electrical current in a second direction, wherein the first direction is not the same as the second direction.