Continuous Graphene Production via High Surface-to-Volume Flow Channels
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Solution Overview
Problem
Current methods for producing graphene sheets are inefficient due to the use of large quantities of undesirable chemicals, long process times, high energy consumption, and significant material loss, leading to environmental concerns and low production yields.
Innovation Solution
A continuous process involving a reacting slurry of graphite or carbon particles and an intercalant/oxidant in flow channels with a high internal wall-to-volume ratio, allowing for rapid and uniform intercalation/oxidation, and subsequent thermal or mechanical exfoliation to produce isolated graphene sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional chemical methods (Hummers method) are used to produce graphene sheets, then graphene can be obtained, but large quantities of undesirable chemicals are required and significant material loss occurs
Solution Approach 1:
The patent segments the graphite particles into smaller sizes (1-10 micrometers) to increase the surface area to volume ratio, enabling more efficient chemical penetration and reaction. This segmentation allows the oxidizing agents to access more graphite surfaces simultaneously, improving yield while reducing the amount of chemicals needed per unit of graphite processed.
Solution Approach 2:
The patent modifies the chemical parameters by using a specific combination of oxidizing agents (potassium permanganate, sodium nitrate, sulfuric acid) in controlled proportions and concentrations. By optimizing these parameter values and the reaction conditions (temperature, time, mixing rate), the process achieves higher conversion efficiency with reduced chemical consumption and material loss.
2Quantity of substance
If conventional batch processing methods are used, then graphene production can be achieved, but the process time is long and productivity is low
Solution Approach 1:
The patent implements continuous processing where graphite particles are continuously fed into the reaction system, continuously mixed with the oxidizing agents, and continuously processed through the reaction stages. This continuous action eliminates the idle time between batch operations and maintains constant production flow, significantly increasing productivity while maintaining high production volume.
Solution Approach 2:
The patent performs preliminary size reduction of graphite particles before the main oxidation reaction. By pre-segmenting the graphite into smaller particles (1-10 micrometers) beforehand, the subsequent chemical reaction proceeds much faster and more uniformly, reducing the overall process time and increasing the rate at which graphene can be produced.
3Quantity of substance
If conventional chemical oxidation methods are used, then graphene sheets can be produced, but high energy consumption is required
Solution Approach 1:
The patent replaces intensive mechanical mixing and heating with optimized chemical reaction conditions. By carefully controlling the chemical composition, temperature, and flow dynamics, the oxidation reaction proceeds efficiently without requiring excessive mechanical energy input for stirring and heating, thus reducing overall energy consumption while maintaining high graphene output.
4Productivity
If conventional batch processing with large reactors is used, then sufficient graphene can be produced, but the equipment volume and chemical usage are excessive
Solution Approach 1:
The patent utilizes fluid dynamics and hydraulic principles to enhance mixing and heat transfer efficiency. By optimizing the flow patterns, liquid circulation, and slurry movement through the reactor system, the chemical reactions occur more uniformly and completely in a smaller volume, reducing both equipment size and chemical consumption while maintaining high production capacity.
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 reduces chemical usage, shortens production time, increases yield, and minimizes environmental impact by efficiently dissipating heat and maintaining stoichiometric ratios, resulting in high-quality graphene sheets with a high percentage of single-layer or few-layer graphene.
Implementation Method 1
oxidizing agent, or a combination of an intercalant and an oxidizing agent... reactions between the graphite or carbon particles and the intercalant and/or oxidant to form a graphite intercalation compound (GIC) or oxidized graphite
Implementation Method 2
treating natural graphite powder with an intercalant and an oxidant to obtain a graphite intercalation compound (GIC)... reactions between the graphite or carbon particles and the intercalant and/or oxidant to form a graphite intercalation compound (GIC)
Implementation Method 3
A continuous process involving a reacting slurry of graphite or carbon particles and an intercalant/oxidant in flow channels with a high internal wall-to-volume ratio, allowing for rapid and uniform intercalation/oxidation, and subsequent thermal or mechanical exfoliation
Data Source
AI summary
Provided is a method of producing isolated graphene sheets, comprising: (a) providing a reacting slurry containing a mixture of particles of a graphite or carbon material and an intercalant and/or an oxidizing agent; (b) providing one or a plurality of flow channels to accommodate the reacting slurry, wherein at least one of the flow channels has an internal wall surface and a volume and an internal wall-to-volume ratio of from 10 to 4,000; (c) moving the reacting slurry continuously or intermittently through at least one or a plurality of flow channels, enabling reactions between the graphite or carbon particles and the intercalant and/or oxidant to occur substantially inside the flow channels to form a graphite intercalation compound (GIC) or oxidized graphite (e.g. graphite oxide) or oxidized carbon material as a precursor material; and (d) converting the precursor material to isolated graphene sheets.