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It was a surprise to discover that Carbon Nanotubes do not have their own topic.
With the lead-off post below, forum members have a place to store articles and links about developments.
There are many references to carbon nanotubes or related carbon based materials in the forum.
If anyone has the time, it would be good to have the links collected here, for future forum readers who might want to study whatever we've gathered on the subject.
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I'd like to open this new topic with a report of development of a way of capturing carbon directly from the output of large CO2 producing business operations.
https://www.yahoo.com/finance/news/deca … 00881.html
Hart Energy
Decarbonizing with Carbon Nanotubes: The Key to Reaching Net Zero
Madison Ratcliff
Tue, April 12, 2022, 5:00 AM
Presented by:Hart Energy E&P
This article appears in the E&P newsletter. Subscribe to the E&P newsletter here.One of the major conflicts holding oil and gas companies back from implementing carbon capture technology within their portfolios has to do with the matter of cost. It’s no secret that, while beneficial for the environment, most carbon capture projects are expensive endeavors. While businesses in the energy sector look to decarbonize, these costly projects more often than not result in net losses.
Enter SkyNano Technologies, a company founded with solving that specific problem in mind.
“We founded the company with the idea of making valuable materials from CO2 that gave a free-market solution to carbon pollution [and] allowed customers to make an economic choice toward a more sustainable but also better material more cost effective with a higher performance than the materials that they were currently buying,” SkyNano co-founder and CEO Anna Douglas told Hart Energy's E&P.
Founded in 2017, customer and federally funded SkyNano strives to find a more productive use for the emissions through the development of carbon nanotubes rather than sequestering captured CO2 underground.
Benefits for oil and gas
The carbon nanotubes can be used to permanently store CO2 in carbon-based every day materials, according to the SkyNano website. Traditionally, carbon nanotubes are primarily used at scale by the defense and aerospace industries, but the company is looking to introduce a lower-priced carbon nanotube product “that is able to displace more conventional carbon additives with enhanced performance and much better sustainability blueprint,” Douglas said.The biggest appeal for the upstream oil and gas industry specifically comes from the company’s free market solution to capture carbon emissions "without the need to charge oil and gas companies for the service to offtake their CO2," offsetting a hefty economic burden.
“A lot of these major companies are looking at sequestration as their main focus, and it's very costly and it takes a lot of energy, and there's literally like zero economic payback outside of a few federal incentives that really don't offset the entire cost of sequestration,” Douglas said. “This is a net loss for an oil and gas company to decarbonize this way. What's a far better solution for them is just to find a partner who can offtake their CO2 emissions without a cost to them.”
Anna Douglas, SkyNano
“We're differentiated in our synthesis technology,” SkyNano co-founder and CEO Anna Douglas said, explaining the benefits of her company versus competitors.
(Source: LinkedIn)
With the core technology based on Douglas’ electrochemical conversion Ph.D. research, the company uses point source capture technology to retrieve carbon emissions from the atmosphere and employs the carbon nanotube technology to create carbon-based materials, a more efficient and potentially less harmful alternative to storing the emissions beneath the surface.Additionally, while other nanotube technology produces harmful byproducts such as carbon monoxide and pHs, the only byproduct from SkyNano’s technology is oxygen, making it more environmentally friendly than some of its competitors.
“We're differentiated in our synthesis technology,” Douglas said. “The way we're making these materials is just totally different. It's electrochemical liquid phase production in contrast with a thermal chemical gas phase catalytic production, so our technology offers about a 10th of the inner use of conventional nanotube production—no harmful byproducts, which is a big deal in nanotube production.”
Complementary to renewables
While most oil and gas companies are at least experimenting with renewable energy sources, as Douglas explained, “there's really only so far that a lot of companies can go with electrification and renewables.”The importance of renewables in the sector shouldn’t be underestimated, but since most of the sector has resolved that the solution for the future of energy is a hybrid combination of traditional and renewable energy sources, businesses need ways to offset emissions from their traditional operations. The SkyNano carbon nanotubes provide a solution to dispose of the preexisting emissions already in the atmosphere.
“We see a lot of heavy emitters making commitments toward decarbonization but without really like a clear pathway of exactly how to accomplish those pledges,” Douglas said. “We just see this huge gap that can be filled with point source capture opportunities, so that's really why we've started there.”
Douglas sees point source capture and reallocation of the emissions as not only the most effective method of decarbonization, but also the fastest. Moving closer to 2050 net-zero targets, she encourages the oil and gas sector to partner with companies that can put their unwanted and harmful emissions to good use.
“The traditional methods we've used to decarbonize other industries don't necessarily always work immediately to get to net zero, so I think point source capture is a very important piece of that puzzle,” she added. “[The emissions] will never be remitted, I think, is a very important piece of getting to net zero. It can be used as a puzzle piece in collaboration with some of these other [renewable] efforts.”
The article above appears to be a "forward looking" puff piece, so please take it with a grain of salt.
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mostly in the cabling for the space elevator and climber topics where we have computed the mass of such and why we are not able to get to orbit by those methods.
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This post is inspired by Void's discovery of significant advances in the use of carbon to conduct electricity. I asked Google's Gemini to investigate to see what news there might be, and it found that carbon can greatly improve the performance of existing copper wires.
Conversation with Gemini
Carbon Nanotube Conductor - Hi Gemini! Thank you for your assistance with many previous requests! A member of our small international forum published a link to a report of discovery or perhaps invention of a way of using carbon nanotubes to conduct electricity. This could, (if true) represent a major change in the outlook for renewable energy, because of a perceived lack of copper. Please investigate this report. What I'm hoping you might be able to find is any indication of current carrying capacity. For example, could this material be used to replace copper in nuclear reactors, which currently consume significant quantities of copper.
Based on the available research, here is an overview of the current status of carbon nanotubes (CNTs) as electrical conductors.
Current Carrying Capacity
CNTs, especially when combined with copper in a composite material, have shown a significantly higher current carrying capacity (ampacity) compared to pure copper. While pure copper wires fail at a current density of around 10^6 A/cm², certain CNT-copper composites have been shown to withstand current densities up to 100 times higher, or approximately 6 x 10^8 A/cm². This is because the CNTs in the composite material suppress the diffusion of copper atoms, which is the primary cause of failure in traditional copper wires at high current densities.
Electrical Conductivity
While individual, perfectly structured CNTs can have a conductivity higher than copper, the challenge is in scaling this to a usable wire or cable. When millions of CNTs are bundled together, their overall conductivity is often reduced due to contact resistance between the individual tubes. However, a significant amount of research is focused on improving this.
Pure CNTs: Early CNT wires had much lower conductivity than copper. Newer research has produced CNT wires with conductivity approaching that of aluminum.
CNT-Copper Composites: A promising approach is to create a composite material by incorporating CNTs into a copper matrix. These composites have been developed with conductivity values comparable to or slightly lower than pure copper. For instance, some composites have achieved a conductivity of 4.7 x 10^5 S/cm, which is close to copper's 5.8 x 10^5 S/cm. Some studies even report a specific electrical conductivity (conductivity per unit mass) that is 56% higher than copper.
Potential to Replace Copper
The potential for CNTs to replace copper is largely driven by their high strength and low density, which could lead to significant weight savings.
Weight Reduction: CNTs have a very low density (1.3 to 1.4 g/cm³), which is significantly less than copper (8.96 g/cm³). This makes them an attractive alternative for applications where weight is a critical factor, such as in aerospace and electric vehicles. Research has shown that replacing copper conductors with CNT composites could result in an 80% weight reduction in some cables.
Applications: While a complete replacement for copper in large-scale applications like a nuclear reactor's main power systems is not yet feasible, CNT composites show promise for specific, high-performance applications. These include lightweight power transmission cables, wiring in aircraft and satellites, and on-chip interconnects in microscale electronics where high ampacity is essential.
Thank you! This preliminary report is both informative and encouraging. The detail about increasing current carrying capacity of existing copper wires is quite surprising.
That's a great point. The use of carbon nanotubes to enhance existing copper wires is one of the most promising applications of the technology. While entirely replacing copper with CNTs is a long-term goal, using them to create high-performance copper-CNT composites is a much more immediate and viable solution.
This approach addresses a key limitation of copper. As you mentioned, at high current densities, copper can fail due to a process called electromigration, where the flow of electrons dislodges copper atoms, creating voids and eventually breaking the circuit. The addition of CNTs to the copper matrix acts like a microscopic scaffolding, preventing this diffusion and dramatically increasing the material's current carrying capacity and durability.
In essence, you get the best of both worlds: the excellent electrical conductivity of copper, enhanced by the structural integrity and high thermal stability of carbon nanotubes. This makes such composites suitable for specialized applications where both high current and light weight are critical, such as in aerospace, electric vehicles, and certain high-power electronics.
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In this conversation, I asked Gemini to explain how it is possible for carbon, which has been used for conduct of electricity for centuries, to perform at such a superior level when organized as carbon nanotubes.
I posted our conversation in our small international forum, and now I have a follow up question. Carbon has been recognized as a conductor of electricity since at least the early 1800's. I understand that graphite is the structure that has been used for conducting electricity. However, graphite is not superior to many other materials for this purpose. Our discussion of carbon nanotubes used for conduct of electric current inspires this question: What is different about the arrangement of atoms in carbon nanotubes that so greatly increases their current carrying capacity?
This is an excellent question that gets to the heart of why carbon nanotubes are such a revolutionary material. The key difference lies in their atomic arrangement and the resulting electron behavior.
Graphite's Structure and Conduction
Graphite is made of multiple, stacked layers of carbon atoms arranged in a flat, hexagonal lattice. Each layer is called graphene. Within a single graphene layer, the carbon atoms are connected by strong covalent bonds. However, the layers themselves are held together by much weaker forces, called van der Waals forces.
Because of this layered structure, electrons can move easily within a single graphene layer, but they are highly restricted from jumping between layers. This is why graphite is a decent conductor, but not exceptional—the weak interlayer forces create resistance and limit the overall current flow through a bulk piece of the material. The electrons essentially follow a two-dimensional path, and a typical conductor would be a block of these layers.
Carbon Nanotube's Structure and Conduction
A carbon nanotube is essentially a single, seamless sheet of graphene rolled into a cylinder. This cylindrical shape eliminates the weak van der Waals forces that exist between layers in graphite. The carbon atoms are all connected by the same strong covalent bonds, forming a continuous, perfectly ordered, one-dimensional structure.
This unique structure allows for a phenomenon called ballistic transport, where electrons can travel for long distances through the nanotube without being scattered or encountering resistance. Think of it like a perfectly smooth, straight tunnel for electrons, whereas graphite is like a series of connected, but separate, rooms. In a traditional conductor like copper, electrons constantly collide with impurities and other atoms, which is the source of electrical resistance and heat. In an ideal carbon nanotube, this scattering is minimal.
The ability for electrons to travel ballistically is what allows carbon nanotubes to have an extraordinarily high current carrying capacity. This is also why they are so effective when used in a composite with copper; they help provide a path for the electrons that bypasses the imperfections in the copper lattice, allowing the material to handle much higher current densities before failing.
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This next conversation resulted in a reply that includes a link to a video about making CNT fiber at Rice University
https://www.youtube.com/watch?v=LiE3VTc0D6w
In light of the fact that our forum includes entrepreneurs, or are employees of forward looking companies, do you have any information on what is required to create carbon nanotubes for this application? My understanding is/was that to date it has been difficult to create carbon nanotubes of any length. Has that problem been solved? If now, how are short lengths of these tubes arranged to perform as current carriers?
That's a very practical and forward-looking question, especially for those in business and manufacturing. The length and arrangement of carbon nanotubes (CNTs) are indeed two of the biggest challenges in scaling up this technology.
The Challenge of Creating Long Nanotubes
You're right, it's been difficult to grow long CNTs. The most common methods for producing CNTs, such as chemical vapor deposition (CVD), tend to produce a tangled mat of short tubes. The growth of a CNT is typically limited by the lifespan of the metal catalyst particle it grows from. These catalysts get poisoned or coated with carbon over time, stopping the growth of the nanotube.
While researchers have been successful in growing CNTs up to several centimeters in a lab setting, creating a continuous, meter-long, or even kilometer-long nanotube is still a major hurdle. So, the problem of creating "infinitely" long tubes for a single-strand wire has not been solved for commercial production.
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How Short Nanotubes Are Arranged to Perform as Conductors
Since long, individual CNTs are not yet a reality for commercial use, the solution lies in arranging short nanotubes into a larger, macroscopic structure. This is where the innovation happens, and it's a critical area for companies to focus on.
The main approach is to take these short nanotubes and assemble them into larger, continuous, and highly aligned structures. This is typically done in one of two ways:
Spinning into Yarns or Fibers: A common method is to "spin" the short CNTs into a yarn or fiber, much like how cotton or wool is spun into thread. This process, often called drawing or spinning, takes the entangled mat of CNTs (often called a "forest") and pulls and twists them into a continuous filament. By twisting them, the van der Waals forces between the individual tubes create a strong, continuous material.
Dry Spinning: This method pulls CNTs directly from a vertically grown "forest" and twists them into a yarn. This can produce fibers with very high alignment and strength.
Wet Spinning: Here, CNTs are dispersed in a liquid and then extruded through a small hole (a spinneret) and into a coagulation bath, where they assemble into a continuous fiber. This method is often more scalable for larger volumes.
Creating Films or Sheets: Short CNTs can also be arranged into thin, conductive films or sheets. This is achieved by techniques like electrophoresis or flow-based alignment, where an electric field or fluid flow is used to orient the nanotubes in a specific direction on a substrate. These films are then used in applications like transparent electrodes or flexible electronics.
The goal in all these methods is to maximize the alignment of the short CNTs. When they are aligned, they can form a network that allows electrons to travel along the length of the conductor with minimal scattering, thus preserving the excellent electrical properties of the individual tubes. This alignment is what distinguishes a high-performance CNT conductor from a simple, randomly oriented mass of CNT powder.
A video showing how researchers at Rice University create strong, conductive fibers from carbon nanotubes in a process that is both "handmade" and "high-tech."
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In this session, I asked a question on behalf of Calliban:
Thank you for the link to the video from Rice University, and for your explanation of how cables can be woven from short nanotubes. One of our members is a mechanical engineer with experience in design of nuclear reactors. He appears to have been unaware of developments in the use of carbon for current as an alternative to copper. Would these new conductors help to reduce costs in construction of a nuclear reactor. You've already indicated that carbon nanotubes can greatly improve the performance of traditional copper conductors. Would this use reduce the cost of copper for a given installation?
That's an insightful question. The short answer is that while the direct replacement of copper with carbon nanotube (CNT) composites would not currently reduce costs, using them to enhance existing copper conductors could lead to significant indirect cost savings over the lifetime of a nuclear reactor.
The Cost of Carbon Nanotubes
At present, the raw material cost of carbon nanotubes is dramatically higher than that of copper.
Copper is a commodity, with a market price typically around $10–$11 per kilogram.
Carbon Nanotubes are a specialty material. Even the cheapest industrial-grade CNTs cost upwards of $100–$200 per kilogram, with more specialized and high-purity variants reaching much higher prices. Some CNT-copper composite cables can cost as much as $375–$500 per kilogram to manufacture.
Therefore, a direct, pound-for-pound substitution of copper with a CNT-based conductor would be prohibitively expensive.
How Costs Could Be Reduced
The cost-saving potential of CNT conductors comes not from a direct material replacement, but from the performance advantages they offer. These advantages could translate into significant cost reductions in the overall design and operation of a nuclear reactor:
Reduced Material Volume: The main benefit you mentioned—a current carrying capacity (ampacity) up to 100 times higher than pure copper—means that a much smaller, lighter cable could be used for the same power load. This reduces the total volume of copper needed for a given installation. For example, a CNT-copper composite cable might require a smaller cross-sectional area and less total length, directly reducing the amount of copper purchased.
Weight and Space Savings: Nuclear reactor containment vessels and other structures are subject to very strict size and weight constraints. Lighter, more compact cables could simplify design, reduce the required structural supports, and potentially allow for a smaller reactor footprint. Less weight and volume also mean lower costs for installation and logistics.
Improved Safety and Longevity: The superior thermal management of CNT-copper composites, combined with their resistance to electromigration, means they can operate reliably at higher temperatures and under greater current loads. This can increase the lifespan of electrical systems, reduce maintenance needs, and enhance safety by lowering the risk of electrical failure, which is a critical factor in a nuclear environment. This long-term reliability and reduced downtime would represent a substantial cost saving.
In summary, while the initial cost of the raw materials would be higher, the use of CNT-enhanced conductors could lead to a net reduction in the overall construction and operational costs of a nuclear reactor by requiring less material, simplifying design, and improving long-term reliability and safety.
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This is the last of the series for today. It covers the difficulty of manufacturing carbon nanotubes and products that contain them.
Whenever a material is valuable but expensive, there is incentive to find a way to create the product at less expense in order to win over existing customers and to attract new ones. Why is manufacture of these tubes and the products made from them so expensive at present?
That's a very perceptive question. You are correct that market incentives drive companies to reduce costs, and the high price of carbon nanotubes (CNTs) is the biggest barrier to their widespread adoption. The high cost is not due to any single factor, but rather a combination of challenges at every step of the manufacturing process.
Here are the primary reasons why CNT manufacturing and the products made from them are so expensive:
1. High Cost of Synthesis and Raw Materials
The most common method for producing CNTs on an industrial scale is Chemical Vapor Deposition (CVD). While more cost-effective than older methods like laser ablation, CVD still has significant expenses:
Expensive Catalysts: The synthesis process requires specialized metal catalysts, such as iron, cobalt, or nickel, to initiate and control the growth of the nanotubes. These high-purity catalysts are a major cost driver.
Energy-Intensive Process: The reactors used for CVD must be maintained at very high temperatures (typically 600–1200 °C) and under controlled atmospheric conditions, making the process highly energy-intensive.
Low Yield and Purity: The CVD process often produces a mix of different types of carbon, including amorphous carbon and other carbon structures, along with the desired nanotubes. The initial "as-produced" material is not pure, which leads to the next major cost.
2. Purification and Sorting Challenges
This is arguably the most significant cost driver. The as-produced CNT material is a chaotic mixture of different types of nanotubes (single-walled, multi-walled), different diameters, and different electrical properties (metallic vs. semiconducting). It is also contaminated with residual catalysts and other carbonaceous impurities.
Purity: Removing these impurities requires complex and often harsh chemical treatments, like acid washing, which can damage the CNT structure and reduce their performance.
Separation: For many high-end applications, a specific type of nanotube is needed. For example, some electronics require only semiconducting nanotubes, while conductors need metallic ones. The separation of these different types is extremely difficult and expensive, often relying on specialized and time-consuming techniques like density gradient ultracentrifugation or chromatography.
3. Challenges in Scaling Up and Consistency
Taking a process that works well in a lab and scaling it up to commercial volumes is a major hurdle.
Batch-to-Batch Inconsistency: It is difficult to ensure that every batch of CNTs has the same properties (length, diameter, purity). This lack of consistency makes it challenging for manufacturers to guarantee product performance and reliability.
Equipment and Automation: Large-scale production requires specialized, high-cost equipment for both synthesis and post-processing (purification, alignment, etc.). The automation of these complex steps is still a developing field, contributing to high labor costs.
4. Downstream Processing and Assembly
Even after producing high-quality CNTs, a significant amount of work (and cost) is required to turn them into a usable product like a wire or composite.
Alignment: As we discussed, short CNTs must be carefully aligned to create a high-performance conductor. Methods like "spinning" or "drawing" require specialized machinery and precise process control.
Integration: When creating CNT-copper composites, ensuring uniform dispersion of the CNTs within the copper matrix is a non-trivial process. Poor dispersion can lead to structural defects and reduced performance.
In conclusion, while the inherent properties of carbon nanotubes are remarkable, their manufacturing is not yet as refined as that of a commodity metal like copper. The cost is a direct reflection of the complexities involved in synthesizing, purifying, and assembling them with the required precision and consistency. As research continues and manufacturing processes mature, these costs are expected to come down, making CNT conductors more economically viable in a wider range of applications.
Thank you for this sobering conclusion to our conversation on a fascinating subject.
You're welcome! I'm glad I could provide a clear and comprehensive view of the subject, from the exciting potential of the technology to the practical challenges of its current cost. It's a field with incredible promise, but like many cutting-edge innovations, it will take time and further development to overcome the manufacturing hurdles.
If you or your forum members have any more questions about carbon nanotubes or any other topics, please don't hesitate to reach out.
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