Danh mục: Science – Technology

A self-assembled composite of graphene oxide and chitosan can capture gold from electronic waste many times more efficiently and selectively than existing materials, researchers in Singapore have shown. The material could potentially eliminate several purification steps and make industrial recycling more economically competitive.

Because of the inertness of gold, its mining has a significant environmental footprint, usually requiring toxic chemicals such as mercury or cyanide to extract it from other components of the ore. This stability, together with its high electrical conductivity and ductility, makes it useful in electronics. Recycling gold to reduce mining faces the same extraction problems. Unwanted components are decomposed using one of several possible processes such as immersion in aqua regia (a concentrated mixture of hydrochloric acid and nitric acid). This yields a mixture of gold(I) and gold(III) ions mixed with copper, nickel, zinc and many others. ‘Now electrolysis is used,’ says Daria Andreeva at the National University of Singapore; ‘Electrolysis is a very long process that can take days or even weeks, so it’s a very interesting approach to look at how to make [separation] more efficient from an energy or time point of view.’

In previous work, Andreeva and colleagues led by Kostya Novoselov – who shared the 2010 Nobel prize in physics with Andre Geim for his work on graphene – developed self-assembled membranes from graphene oxide and other materials for applications ranging from tunable water filtration to corrosion prevention. In the new work, the researchers combined a solution of chitosan with a dispersion of graphene oxide flakes. When freeze dried, it formed a sponge-like material with ion-binding sites that could selectively capture and reduce both gold(I) and gold(III) ions – which must usually be extracted separately. Their material demonstrated substantially higher capacity to adsorb both ions: previous adsorbents have captured around 0.3g gold(I) and 2g gold(III) per gram of adsorbent – theirs captured 6.2g gold(I) and 16.8g gold(III).

Moreover, their material did not require an electrical input – the material could donate sufficient electrons. ‘It’s a two-stage process,’ explains Novoselov. ‘The ions adsorb fairly tightly, but then we reduce them into the metallic state and we get nanocrystals of gold. These nanocrystals are not chemically adsorbed but only van der Waals adsorbed, so it is easier to remove them.’ The researchers are now working to develop a better understanding of the mechanism and to improve the specificity for gold still further. ‘In e-waste there is a thousand times more copper than there is gold,’ says Novoselov. ‘So while this is better than traditional materials, it’s still an open question whether it’s good enough for industry.’

‘This is really good,’ says Yang Su at Tsinghua University in China, who in 2022 co-authored a paper with Geim and others on gold extraction using reduced graphene oxide. ‘The adsorption capacity is astonishingly high.’ He notes the paper ‘shows us that there are a lot of things we didn’t know before about graphene systems and their chemistry’. He says he will be interested to see more detailed theoretical modelling of how the system can supply enough electrons to reduce so many gold cations with no applied voltage. He also hopes similar ideas might be useful in other metals, pointing out that if electric vehicles take over there will be a lot of unwanted platinum in catalytic converters to recycle.

References
K Yang et al, Proc. Natl. Acad. Sci. USA, 2024, 121, e2414449121 (DOI: 10.1073/pnas.2414449121)

As industries around the world push the boundaries of innovation, materials science has become a foundational component of technological advancement. Few materials embody this potential more than graphene. A single layer of carbon atoms arranged in a hexagonal lattice, graphene has captured the attention of scientists and engineers due to its exceptional properties. BIGNANOTECH, a pioneering provider of high-tech graphene materials, is leveraging graphene’s extraordinary characteristics to provide high-quality graphene ink and graphene powder solutions. These products are not only cutting-edge but also have the potential to drive progress across multiple industries.

What is Graphene? The Science Behind the “Miracle Material”

Graphene was first isolated in 2004 by researchers Andre Geim and Konstantin Novoselov, an achievement that earned them the Nobel Prize in Physics in 2010. Graphene is unique because it consists of a single layer of carbon atoms bonded in a two-dimensional hexagonal lattice, a structure that imparts some extraordinary properties:

• Exceptional Strength: Despite being just one atom thick, graphene is about 200 times stronger than steel. This makes it one of the strongest materials ever discovered, while remaining incredibly lightweight.
• Superior Electrical Conductivity: Graphene’s unique structure allows electrons to move through it at an extremely high speed, making it an excellent conductor. It’s more conductive than copper and ideal for applications requiring efficient energy transfer.
• Thermal Conductivity: Graphene has impressive heat conductivity, enabling efficient heat dissipation, which is crucial in electronics where overheating is a constant challenge.
• Flexibility and Transparency: Graphene is also flexible and nearly transparent, making it ideal for applications in flexible electronics, optoelectronics, and even in next-generation displays.

These properties make graphene an ideal candidate for applications across industries like electronics, energy, medical devices, aerospace, and beyond. As graphene continues to make its mark on the high-tech materials landscape, BIGNANOTECH’s contributions to this sector are helping companies capitalize on the material’s full potential.

Graphene Ink: Redefining the Future of Electronics and Beyond

One of BIGNANOTECH’s flagship products, graphene ink, is set to revolutionize the realm of printed electronics. Traditional conductive inks, which often rely on precious metals like silver, present challenges due to their cost, weight, and environmental impact. Graphene ink, on the other hand, offers a high-performance alternative that addresses these limitations and opens new avenues for electronic manufacturing.

Advantages of Graphene Ink

1. Enhanced Electrical Performance: Graphene ink provides higher electrical conductivity than traditional inks. Its atomic structure allows for superior electron mobility, which translates into faster data transfer and more reliable performance in electronic devices.
2. Environmentally Sustainable: Unlike metal-based conductive inks, graphene ink is a carbon-based material, which aligns with environmentally sustainable production practices. This makes it particularly appealing to companies focused on reducing their carbon footprint.
3. Cost-Effective and Efficient: Graphene ink is less expensive than traditional metal-based inks, especially since it can achieve high conductivity at lower concentrations. This cost-effectiveness is beneficial in large-scale production scenarios.
4. Broad Applicability: The potential uses for graphene ink are vast, spanning from flexible sensors and RFID tags to wearable electronics and solar cells. For example, in wearable devices, graphene ink offers comfort and durability, as it remains functional under bending and stretching.

Applications of Graphene Ink

The versatility of graphene ink allows it to be applied in numerous fields:

• Wearable Electronics: Graphene’s flexibility and conductivity make it ideal for developing lightweight, wearable tech such as fitness trackers, medical sensors, and smart clothing.
• Printed Sensors: Graphene ink enables the creation of flexible and thin sensors that can be printed onto various surfaces. These sensors are critical in industries like healthcare, where monitoring patient vitals in real-time is essential.
• Energy Harvesting: In renewable energy applications, graphene ink’s conductive properties make it a powerful component in creating more efficient solar cells, leading to cleaner, sustainable energy solutions.

BIGNANOTECH’s graphene ink is meticulously crafted to ensure quality, consistency, and adaptability, making it a preferred choice among researchers and manufacturers alike.

Graphene Powder: A Multi-Functional Solution with Wide Applications

Alongside graphene ink, BIGNANOTECH also produces high-quality graphene powder, a versatile material that has gained traction in industries that demand durability, strength, and flexibility. Graphene powder serves as a critical ingredient in applications ranging from energy storage to composite materials.

Benefits of Graphene Powder

1. Enhanced Mechanical Properties: When added to other materials, graphene powder can significantly increase strength and flexibility. This makes it an invaluable component in industries such as aerospace, automotive, and construction, where durable, lightweight materials are essential.
2. Energy Efficiency: Graphene powder’s high conductivity benefits energy storage solutions, such as batteries and supercapacitors, where efficient charge and discharge cycles are required.
3. Thermal Regulation: Due to its excellent heat conductivity, graphene powder is used in thermal management solutions, especially in electronics and automotive industries where heat dissipation is a major concern.

Applications of Graphene Powder

Graphene powder’s adaptability makes it suitable for various applications:

• Battery Technology: Graphene powder can enhance the energy storage capacity and lifespan of batteries, which is critical in the era of electric vehicles and renewable energy storage.
• Composite Materials: Graphene powder, when incorporated into plastics, metals, and other materials, can improve strength-to-weight ratios. This application is pivotal in the aerospace and automotive industries, where lightweight and resilient materials are essential for performance.
• Thermal Management in Electronics: As electronic devices become smaller and more powerful, managing heat has become a significant challenge. Graphene powder offers a solution for thermal regulation, helping prevent overheating in devices.

BIGNANOTECH’s commitment to quality ensures that their graphene powder is of the highest purity and performance standards, making it suitable for even the most demanding applications.

Why Choose BIGNANOTECH for High-Tech Graphene Materials?

BIGNANOTECH stands out as a leader in the graphene market not only for the quality of its products but also for its dedication to advancing scientific and technological boundaries. Here are a few reasons why BIGNANOTECH is a preferred partner for businesses looking to harness the power of graphene:

1. Uncompromised Quality: BIGNANOTECH follows rigorous quality control procedures to ensure the purity and consistency of their graphene materials. This commitment to quality gives businesses confidence in the performance of their products.
2. Scientific Expertise: The company employs a team of experts in materials science and engineering who continuously work to improve and innovate graphene applications.
3. Sustainable Approach: BIGNANOTECH is dedicated to environmentally friendly production methods, positioning it as a forward-thinking company in a market that values sustainability.

The Future of Technology with BIGNANOTECH’s Graphene Solutions

Graphene is still in its early stages of adoption, but the potential applications continue to grow. From revolutionizing electronics and energy storage to creating stronger, lighter, and more durable materials, graphene’s impact on technology and industry cannot be overstated. With BIGNANOTECH’s graphene ink and graphene powder, businesses have the opportunity to be part of a high-tech future where efficiency, performance, and sustainability come together.

Conclusion

The future is being built with graphene, and BIGNANOTECH is paving the way. Whether you are in electronics, energy, healthcare, or aerospace, BIGNANOTECH’s high-tech graphene materials can bring unparalleled value to your products. Their graphene ink and graphene powder are more than just materials – they are tools to transform and elevate industry standards. With the power of graphene, companies can create faster, more efficient, and more resilient products, driving innovation in an increasingly competitive market.

Choose BIGNANOTECH to lead your industry with high-quality, high-performance graphene solutions that are ready to meet the demands of the future.

Graphene looks set to disrupt the electric vehicle (EV) battery market by the mid-2030s, according to a new artificial intelligence (AI) analysis platform that predicts technological breakthroughs based on global patent data.

With the global transition towards an electrified transportation system gathering pace, the search for the perfect EV battery – offering the ideal balance of cost, energy density, safety and environmental sustainability – becomes ever more salient. There are around a dozen battery chemistries vying for market dominion; which one will emerge victorious is the veritable trillion-dollar question. For the near-term at least, traditional lithium-based batteries are likely to maintain their grip on the market, with sodium-based batteries offering a cheap and green alternative for certain applications, according to new research from Focus, an AI analysis platform that predicts technological breakthroughs based on global patent data. It is the emergent graphene and dual-ion batteries, however, that are likely to truly disrupt the market one day.

The research suggests that graphene batteries in particular will emerge in the early to mid-2030s to challenge their lithium counterparts for the EV crown, as the price of graphene production falls precipitously. This development promises to not only vastly improve EV performance but also offer a boon to energy efficiency and carbon reduction targets. “If there is one battery technology to keep an eye on, it is graphene,” says Jard van Ingen, Focus’s CEO and co-founder.

The young pretenders

Focus analyses the current state of EV battery chemistries and forecasts which ones look set to dominate in the years ahead. Using an approach inspired by research from the Massachusetts Institute of Technology, the Focus platform processes large volumes of global patent data in real time using three types of AI: large language models do continuous research into global patent data archives for tech scouting, scoring and comparisons; vector search provides real-time intelligence on the global innovation and technology landscape; and multivariate regression offers predictive analytics by identifying relationships between data and real-world outcomes. Focus calculates ‘Technology Readiness Levels’ for the maturity of battery technologies and a ‘Technology Improvement Rate’ to measure the increase in performance per dollar per year of different battery chemistries.

“In essence, for EVs, it is all about finding that sweet spot between energy density, safety, cost and sustainability,” says Kacper Gorski, Focus’ head of operations. “Each of these chemistries brings something unique to the table, and their development will shape the future of electric mobility. The key question is, however, which are actually progressing fast and which are over-hyped?”

Focus found that all lithium-based battery technologies are improving at similar speeds. The current dominant chemistries, lithium-nickel-manganese-cobalt and lithium-iron-phosphate, are improving year-on-year (YoY) at rates of 30% and 36%, respectively. Lithium sulphur batteries are improving at 30% YoY and silicon anodes at 32%, meaning the pair are unlikely to disrupt the market – truly disruptive technologies have improvement speeds that are significantly and consistently higher than their competitors. Similarly, although much has been written about the potential of solid-state lithium batteries, Focus found the technology is only improving at a rate of 31% YoY, meaning it too is unlikely to disrupt the incumbents.

The same goes for similarly hyped sodium batteries, which have a 33% improvement rate – putting them within a measurement error of lithium-iron-phosphate batteries. Van Ingen explains that sodium batteries have a relatively modest energy density, limiting the mileage they can offer EVs without adding too much weight to the vehicle. They would, however, make sense for stationary storage, where weight is not a limiting factor. “So if all you need is relatively cheap batteries for grid demands, then sodium-batteries make a lot of sense,” he says. “They could even work for lower-end EVs – really cheap, high volume–production vehicles designed for short distances. It is a relatively fast improving technology, it is just not going to completely disrupt the market.”

It is some of the more nascent battery chemistries that are generating the most excitement. Magnesium-sulphur batteries are improving at a rate of 24.4% YoY, magnesium-ion batteries at 26%, nanowire batteries at 35% and potassium-ion batteries at 36%. However, these all pale in comparison to graphene batteries, which are improving at a whopping 48.8% YoY, or dual-ion batteries, which boast a 48.5% YoY improvement rate. “Because the improvement speeds of graphene and dual-ion batteries are significantly and consistently higher than other battery chemistries’, these can be considered disruptive,” says van Ingen.

However, in a head-to-head between the two chemistries, Focus believes graphene batteries hold the higher potential, as the research is more developed and the element more ubiquitous. The technology offers a huge step up for the performance of EVs, promising high energy densities, increased cycle life (the number of charge and discharge cycles a battery can complete before losing performance) and fast charging. Its main downside at present is its prohibitive cost, driven by the eye-wateringly expensive price tag of graphene production.

“Graphene is a really basic material derived from any carbon source,” says van Ingen. “The base material is really plentiful, it is all over the place, but the way to turn it into graphene is the limitation. Current production methods are way too expensive.”

Graphene batteries, the true disruptor

For graphene batteries to disrupt the EV market, the cost of graphene production must come down significantly. Graphene is currently produced at around $200,000 per ton, or $200 per kilogram (kg). It is difficult to predict how cheap production needs to be before manufacturers start to use it in their batteries, but Focus believes this will happen when graphene becomes comparable with lithium.

Lithium carbonate currently costs around $16/kg to produce and analysts believe it could fall a further 30% to $11/kg in 2024. Focus’s forecasting method estimates the improvement speed of graphene production at 36.5% YoY. So, assuming the current price of $200/kg and a target price of $11/kg, Focus forecasts graphene production will become cheap enough for the material to force its way into battery chemistries by around 2031.

According to Focus, there are around 300 organisations currently working on graphene battery technology. Of the top ten companies best positioned to disrupt the battery market with graphene, Focus ranks Global Graphene Group as the leader. Its subsidiary, Honeycomb Battery Company, recently announced a landmark combination deal with Nubia Brand International aimed at enhancing Honeycomb’s manufacturing and research capabilities, with a primary focus on advanced battery technology for EVs.

Similarly, StoreDot, the only start-up in the top ten, has made impressive progress in 2023. The company is set for mass production of its ‘100in5’ battery cells in 2024. These cells are designed to deliver at least 100 miles of range with just five minutes of charging. StoreDot has formed strategic agreements with the likes of Volvo Cars (Geely), VinFast and Flex|N|Gate. In early 2024, it collaborated with Volvo Cars’ Polestar on the world’s first ten-minute EV charging demo. Its battery quality has been validated after testing by 15 leading global manufacturers, showing no degradation even after 1,000 consecutive ‘extreme fast charging’ cycles.

Toray Industries, on the other hand, has been identified by Focus as the fastest iterating player (the lowest cycle time). The company has made significant progress in its graphene battery research, developing an ultra-thin graphene dispersion solution with excellent fluidity and electrical and thermal conductivity – particularly beneficial for applications such as battery and wiring materials. Toray is thus able to create very thin, high-quality graphene from inexpensive graphite materials. The technology, claims Toray, offers a 50% better battery life than traditional carbon nanotubes used as conductive agents​.

“Looking ahead, the biggest bottleneck now for graphene batteries is to find a production method that can really do it at scale,” concludes van Ingen. It is still a field mostly dominated by research, but this will catapult it out into the real world within the next decade, according to Focus.

Source: Energy Monitor

No need to wear uncomfortable smartwatches or chest straps to monitor your heart rate if your comfortable shirt can do the job better. This is the idea driving the “smart clothing” developed by a lab at Rice University.

The Brown School of Engineering lab, led by molecular and chemical engineer Matteo Pasquali, reports in the American Chemical Society’s journal Nano Letters that they have sewn carbon nanotube fibers into sportswear to monitor heart rate and continuously record the wearer’s electrocardiogram (ECG).

According to the research team, these fibers conduct electricity like metal wires but are washable, comfortable, and less likely to break when the body moves. Overall, the enhanced shirt can collect data better than standard chest strap monitors that take direct measurements during trials. When combined with commercial medical electrode monitors, the carbon nanotube shirt provides better ECG results.

Lauren Taylor, the study’s lead author, said, “The shirt needs to be snug against the chest. In future research, we will focus on using denser arrays of carbon nanotube fibers to increase the surface area in contact with the skin.” The researchers noted that the nanotube fibers are soft and flexible, and clothing incorporating them can be machine washed. The fibers can be machine-sewn into fabric like standard thread.

The zigzag stitching pattern allows the fabric to stretch without breaking the fibers. Taylor noted that the fibers not only provide stable electrical contact with the wearer’s skin but also serve as electrodes to connect electronic devices such as Bluetooth transmitters that relay data to smartphones or connect to Holter monitors that can be stored in the user’s pocket.

Pasquali’s lab introduced carbon nanotube fibers in 2013. Since then, these fibers, each containing tens of billions of nanotubes, have been studied for use as bridges to repair damaged hearts, electrical interfaces with the brain, use in cochlear implants, flexible antennas, and applications in automotive and aerospace industries.

Their development is also part of the Carbon Hub based at Rice—a multidisciplinary research initiative led by Rice and launched in 2019. The original nanotube fibers, about 22 microns wide, were too thin for a sewing machine to handle. Taylor said a rope maker created a thread that could be sewn, essentially three bundles of seven fibers each, braided into a size comparable to standard thread.

Taylor explained, “We worked with someone who sells small machines designed to make ropes for model ships. He built us a mid-scale device that works similarly.” The zigzag pattern can be adjusted to account for the stretch of the shirt or other fabrics. Taylor said the team is working with Dr. Mehdi Razavi and his colleagues at the Texas Heart Institute to find ways to maximize skin contact.

The research team notes that fibers woven into fabric can also be used to embed antennas or LEDs. Minor modifications to the fiber’s shape and related electronics could eventually allow clothing to monitor several vital signs—exertion levels or breathing rates.

Taylor noted that other potential applications might include human-machine interfaces for cars or soft robots, or as antennas, health monitors, and ballistic protection in the military. Taylor commented, “We demonstrated with a collaborator a few years ago that carbon nanotube fibers dissipate energy on a per-weight basis better than Kevlar.”

Pasquali commented, “We have found that after two decades of development in labs worldwide, this material performs well in many applications. Due to the combination of conductivity, good skin contact, biocompatibility, and softness, carbon nanotube fibers are a natural component for wearable devices.”

Pasquali believes that while the wearable device market is relatively small, it could pave the way for a new generation of sustainable materials created from hydrocarbons through direct splitting—a process that also produces clean hydrogen. Developing such materials is a core focus of the Carbon Hub. Pasquali concluded, “We are in a situation similar to solar cells a few decades ago. We need application leaders who can create the momentum to scale up production and increase efficiency.”

Researchers from various institutes in Barcelona and Germany have demonstrated that a hybrid material consisting of a monolayer of graphene and a metallic grating structure is an excellent candidate for relevant commercial applications in which efficient nonlinear conversion of (invisible) terahertz light is required. This work has just been published in ACSNano, in a paper with Dr Klaas-Jan Tielrooij, leader of the ICN2 Ultrafast Dynamics in Nanoscale Systems group, as last author. Metal grating combined with graphene opens up the road to terahertz nonlinear photonic applications.

Nonlinear optical conversion – i.e. the process by which an incident light beam of a certain wavelength turns into rays of different wavelengths, due to its interaction with the material it passes through – is relevant to for many current and future technologies, such as imaging, information storage and processing, telecommunication, quantum technologies, and other fields.

The ideal material for these applications should provide, first of all, a very high conversion efficiency, which means that a significant fraction of the incoming beam has to be converted into light of the desired wavelengths. It is also required to have a small footprint (that is, as little material as possible has to be used); to be compatible with standard CMOS technology used in most electronic devices; and to be able to operate at room temperature. Particularly needed is an optimal solution for applications in which the incident light is in the terahertz (THz) region of the electromagnetic spectrum. This light cannot be seen by the human eye, yet it is commonly used for applications ranging from airport security to product inspection, and can play an important role in future communication technologies.

Two-dimensional materials are highly interesting for light conversion. They consist of a single layer (or a couple of them) of atoms and thus have almost zero-thickness (this is why they are called 2D materials). This characteristic ensures a small material footprint. In addition, since they are thinner than the wavelength of light, the optical waves propagating in these materials remain in phase. Among them, graphene, a by-now-well-known material made of a monolayer of carbon atoms arranged in a honeycomb structure, is particularly promising. This is because it exhibits very large nonlinear conversion coefficients, especially in the THz range. On the other hand, though, its extremely reduced thickness affects its conversion efficiency, due to the small quantity of matter the light can interact with. To overcome this problem, the authors decided to combine graphene with another material system that enhances this interaction.

A team of researchers from the Catalan Institute of Nanoscience and Nanotechnology (ICN2, Spain), the Helmholtz-Zentrum Dresden-Rossendorf (HZDR, Germany), the Institute of Photonic Sciences (ICFO, Spain), the Max Planck Institute of Polymer Research, Mainz (Germany), the University of Bielefeld (Germany) and the Technical University of Berlin (TUB, Germany) have combined graphene with a metallic structure that provides field-enhancement, leading to a hybrid material characterized by very high nonlinear light conversion efficiency. As explained in a scientific article recently published in ACSNano, this structure (grating-graphene) produces outcoming light at the new wavelength having an intensity more than 1000 times higher than the one obtained using just graphene.

Dr Klaas-Jan Tielrooij, leader of the ICN2 Ultrafast Dynamics in Nanoscale Systems group and last author of the paper explains: “The combination of graphene and a metal grating leads to highly efficient conversion of terahertz light, reaching up to 1% (in field) for rather weak incident light.” Dr Jan-Christoph Deinert, from HZDR, first author of the work, adds: “This hybrid material made it possible for us to observe light that oscillates three times, five times, seven times, and even nine times faster than the incoming light.”

The outstanding conversion efficiency of this hybrid material guarantees low power consumption in the conversion process, while the compatibility of graphene with CMOS technology allows for integration in devices based on such technology. Overall, this grating-graphene structure presents itself as an excellent candidate for commercially viable applications requiring nonlinear conversion in the terahertz regime, chip-integration, room temperature operation and low power consumption.