Graphene thermal conductivity - introduction and latest news
Graphene thermal conductivity
Thermal transport in graphene is a thriving area of research, thanks to graphene's extraordinary heat conductivity properties and its potential for use in thermal management applications.
The measured thermal conductivity of graphene is in the range 3000 - 5000 W/mK at room temperature, an exceptional figure compared with the thermal conductivity of pyrolytic graphite of approximately 2000 W/mK at room temperature. There are, however, other researches that estimate that this number is exaggerated, and that the in-plane thermal conductivity of graphene at room temperature is about 2000-4000 W/mK for freely suspended samples. This number is still among the highest of any known material.
Graphene is considered an excellent heat conductor, and several studies have found it to have unlimited potential for heat conduction based on the size of the sample, contradicting the law of thermal conduction (Fourier's law) in the micrometer scale. In both computer simulations and experiments, the researchers found that the larger the segment of graphene, the more heat it could transfer. Theoretically, graphene could absorb an unlimited amount of heat.
The thermal conductivity increases logarithmically, and researchers believe that this might be due to the stable bonding pattern as well as being a 2D material. As graphene is considerably more resistant to tearing than steel and is also lightweight and flexible, its conductivity could have some attractive real-world applications.
But what exactly is thermal conductivity?
Heat conduction (or thermal conduction) is the movement of heat from one object to another, that has a different temperature, through physical contact. Heat can be transferred in three ways: conduction, convection and radiation. Heat conduction is very common and can easily be found in our everyday activities - like warming a person,s hand on a hot-water bottle, and more. Heat flows from the object with the higher temperature to the colder one.
Thermal transfer takes place at the molecular level, when heat energy is absorbed by a surface and causes microscopic collisions of particles and movement of electrons within that body. In the process, they collide with each other and transfer the energy to their neighbor, a process that will go on as long as heat is being added.
The process of heat conduction mainly depends on the temperature gradient (the temperature difference between the bodies), the path length and the properties of the materials involved. Not all substances are good heat conductors - metals, for example, are considered good conductors as they quickly transfer heat, but materials like wood or paper are viewed as poor conductors of heat. Materials that are poor conductors of heat are referred to as insulators.
How can graphene,s exciting thermal conduction properties be put to use?
Some of the potential applications for graphene-enabled thermal management include electronics, which could greatly benefit from graphene's ability to dissipate heat and optimize electronic function. In micro- and nano-electronics, heat is often a limiting factor for smaller and more efficient components. Therefore, graphene and similar materials with exceptional thermal conductivity may hold an enormous potential for this kind of applications.
Graphene's heat conductivity can be used in many ways, including thermal interface materials (TIM), heat spreaders, thermal greases (thin layers usually between a heat source such as a microprocessor and a heat sink), graphene-based nanocomposites, and more.
Xiaomi launches a graphene radiator capable of heating a room in a few seconds
Xiaomi has released its new Xiaomi Mijia Graphene Skirting Board Heater 2, a graphene radiator that boasts a powerful heating system 2.200W and a foldable format. The Xiaomi Mijia Graphene Skirting Board Heater 2 features a graphene heating technology heater capable of providing heat in just 3 seconds and heating an entire room to the desired temperature in just 15 minutes.
In 2022, Xiaomi launched the Mijia Graphene Baseboard Heater (Fire Edition). The device uses two graphene-based heating elements, and has a simulated flame function that uses an integrated humidifier and LEDs to generate the flame appearance. This new launch seems to be the next generation in the same product line.
Haydale and Jersey Energy Technologies announce underfloor heating pilot in Jersey
Haydale has announced that it has signed a contract with Jersey Energy Technologies ("JET"), a start-up company focused on providing energy efficiency solutions across the Channel Islands, to begin a pilot trial deploying Haydale's underfloor heaters within social housing in Jersey.
Haydale's underfloor heating system utilizes the Company's proprietary HDPlas functionalization technology to unlock the high-level thermal conductivity properties of graphene. Data gathered from Haydale's in-house prototype systems implies up to 30% lower operating cost for their functionalized graphene ink underfloor heating compared to standard wired systems running off mains power. In test conditions, the heaters, which can be uniformly and individually heated, have also shown improvements in flexibility, and durability; reaching maximum temperatures quickly. This presents a potential commercial solution to meet the demand for improved energy efficiency, reducing heating costs for residents without trade off.
Researchers develop scalable graphene technology for regulating heat transfer and enhancing battery safety
Researchers at Swansea University, in collaboration with China's Wuhan University of Technology and Shenzhen University, have developed a technique for producing large-scale graphene current collectors that could significantly enhance the safety and performance of lithium-ion batteries (LIBs).
Their recent study details the first successful protocol for fabricating defect-free graphene foils on a commercial scale. These foils offer excellent thermal conductivity - nearly ten times higher than traditional copper and aluminium current collectors used in LIBs.
Salgenx expands potential applications of its graphene and hard carbon-coated sand
Salgenx, developer of saltwater flow battery technology, has announced the expansion of its development of graphene and hard carbon-coated sand. Originally designed for use in advanced battery systems, Salgenx is now exploring a wide array of new applications for this innovative material, ranging from smart infrastructure to environmental sustainability.
The Company says that "the unique combination of graphene and hard carbon in a sand aggregate has the potential to transform the construction industry". By enhancing the electrical conductivity, mechanical strength, and durability of concrete, Salgenx’s carbon-coated sand opens up new possibilities in building and infrastructure development.
Haydale Graphene Industries and Staircraft report progress on graphene-based underfloor heating trials
Specialist structural flooring manufacturers Staircraft have been testing the use of Haydale's graphene-based functional ink for application on their innovative chipboard flooring system. Significant investment has reportedly been made to get the new flooring system to adopt a heating solution that is cost effective and easy to install.
In a recent trial, Staircraft has reported very encouraging results and is now focused on continuing to collect definitive data before introducing the concept to their customer base.
Graphene Composites USA selected to join U.S Military footwear project
Graphene Composites USA (GC) has been selected to participate in a research and development program between DEVCOM Soldier Center, Natick MA and UMass Lowell, to develop materials for the next generation of U.S. military footwear.
The program, SWIFT [Supporting Warfighters through Innovative Footwear Technologies], is offered by the HEROES (Harnessing Emerging Research Opportunities to Empower Soldiers) initiative and will see GC extend its patented GC Composite graphene and aerogel technology to develop ultra-lightweight, durable, insulative materials for use in extreme cold weather.
Researchers develop new approach for controlling thermal emission
Researchers from the University of Manchester, The Pennsylvania State University, Koç University and Vienna University of Technology (TU Wien) have tackled the challenge of control of thermal radiation, demonstrating a new topology-based approach.
The team explained that conventional approaches to tailoring thermal emission using metamaterials are hampered both by the limited spatial resolution of the required subwavelength material structures and by the materials’ strong absorption in the infrared. In their recent work, the scientists developed an approach based on the concept of topology: by changing a single parameter of a multilayer coating, they were able to control the reflection topology of a surface, with the critical point of zero reflection being topologically protected.
Haydale demonstrates graphene ‘Hot Seat’ at the Advanced Materials Show 2024
Haydale recently displayed, for the first time in public, its revolutionary new solution to automotive seat heating labelled the ‘Hot Seat’ at the NEC in Birmingham. Using the Company's patented process and unique materials, Haydale has developed an alternative to existing automotive seat heating technology.
This interesting graphene application is based on the production of a seat heater that is faster to heat, uses less energy and offers a green and eco-friendly alternative to the current solutions. Using the same technology in place for their Underfloor Heating range of products under development, Haydale has now adapted this to provide a novel application for heated seating.
Graphene-based masterbatches: Marrying performance with ecological responsibility
GrapheneUP®, an industry vanguard in manufacturing verified few-layer graphene and a diverse array of graphene-centric intermediary products, announces the debut of MASTERGUP® — an innovative line of thermoplastic masterbatches. This breakthrough harnesses the transformative potential of graphene, setting a new benchmark for sustainability and recyclability within multiple sectors.
Graphene, distinguished by its exceptional strength and conductivity, imparts enhanced thermoplastic properties, including mechanical robustness, thermal stability, and gas barrier properties. These advancements extend the lifespan of products and significantly reduce waste, thereby contributing to more excellent environmental stewardship. Moreover, incorporating the graphene GUP® into thermoplastic matrices elevates processability, streamlining the molding, reshaping, and recycling processes. GUP®-fortified thermoplastics demonstrate remarkable endurance through repeated recycling, mitigating material degradation — a commendable achievement in material sustainability.
Nottingham houses test graphene-infused infrared wallpaper
A trial is underway in 45 social housing groups across the UK that could revolutionize the way we heat our homes, especially those that have long battled with issues like heat leakage and inefficient insulation. A graphene-enhanced infrared wallpaper, developed by NexGen Heating, is being tested in a project targeting social housing and older properties that are notoriously hard to insulate.
By infusing wallpaper with graphene, NexGen Heating has created a product that emits infrared heat, warming objects and people directly in a manner reminiscent of sunlight. This direct form of heating is not only efficient but also customizable to fit the aesthetics of any room, promising an unobtrusive addition to homes. Furthermore, the potential for integration with solar panels and batteries could make this a cornerstone of sustainable living, significantly reducing reliance on fossil fuels. NexGen Heating says infrared can provide greener, cheaper heating when paired with solar panels and batteries.