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⋅m−1⋅K−1 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⋅m−1⋅K1 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.

Latest Graphene Thermal Conductivity news

Gaming company launches graphene-enhanced SSD

Oct 01, 2017

Team Group, memory solutions and accessory provider, has announced the addition of new products to their existing T-FORCE gaming line of products. Among the new products is the T-FORCE CARDEA ZERO M.2 PCI-E solid-state drive, featuring graphene copper foil cooling on the SSD module allowing the SSD to maximize cooling benefits from both natural passive cooling and directed air cooling via fans to deliver excellent heat dissipation.

Graphene-enhanced gaming drive image

According to the company, the T-FORCE CARDEA ZERO M.2 PCI-E SSD is the world’s first super slim SSD on the market built specifically for gaming laptops and high-performance tablet PCs. Utilizing graphene provided by Nitronix and designing combinations of different proportions of graphene and copper foil, the patented graphene copper foil heat spreader was reportedly achieved through stringent multiple verification. It offers excellent thermal cooling effect even in a closed space.

China-based Tunghsu Optoelectronics unveils new graphene LEDs

Sep 26, 2017

The China-based Tunghsu Optoelectronic Technology has announced a new series of graphene LED ‘super lights’ at the 2017 International Graphene Innovation Conference. The new lights reportedly use graphene for heat dissipation and conduction.

The new LEDs' volume is said to be 75% lower than traditional LED lights and they are 30% lighter. Power-saving capacity is 20-30% better and they provide high-performance luminescence and light distribution. The lights also come with a smart connection function, according to the company. Users can integrate information devices, transmit Wi-Fi hotspots, gather environmental information, monitor road security and act as emergency alarms.

Graphene Handbook

Graphene-enhanced fluid improves solar collectors' efficiency

Sep 13, 2017

Researchers at the University of Lisbon's Centro de Química Estrutural have discovered that the addition of graphene to the working fluid of solar collectors helps to regain some of its lost efficiency. Solar thermal collectors are seen as a simple and inexpensive way to make use of solar energy. Pure water is an efficient heat-transfer fluid, but it must be mixed with antifreeze to prevent damage to pipes during freezing conditions, and this lowers its performance.

Graphene enhances the performance of solar collectors image

The properties of an ideal heat-transfer fluid in a solar collector include a high thermal capacity and a freezing point outside of the temperature range likely to be encountered. Unfortunately, in the case of water, satisfying the latter requirement means compromising on the former, as mixing water with antifreeze makes it a less effective carrier of heat.

Graphene-ceramic composite with impressive properties may be useful for aerospace, sensors and more

Aug 11, 2017

A collaboration work by Purdue, the Chinese Lanzhou University and Harbin Institute of Technology, and the U.S. Air Force Research Laboratory has yielded a lightweight, flame-resistant and super-elastic composite shown to combine high strength with electrical conductivity and thermal insulation, suggesting potential applications from buildings to aerospace.

Graphene composite shows impressive properties image

The composite material is made of interconnected cells of graphene sandwiched between ceramic layers. The graphene scaffold, referred to as an aerogel, is chemically bonded with ceramic layers using a process called atomic layer deposition. The team explained that graphene would ordinarily degrade when exposed to high temperature, but the ceramic imparts high heat tolerance and flame-resistance, properties that might be useful as a heat shield for aircraft. The light weight, high-strength and shock-absorbing properties could make the composite a good substrate material for flexible electronic devices. Because it has high electrical conductivity and yet is an excellent thermal insulator, it might be used as a flame-retardant, thermally insulating coating, as well as sensors and devices that convert heat into electricity, said associate professor in the School of Industrial Engineering at Purdue University.

Graphene Flagship research teams prepare to test graphene's potential for aerospace applications

Jul 08, 2017

The Graphene Flagship has announced preparations for two new experiments in collaboration with the European Space Agency (ESA), to test the viability of graphene for space applications. Both experiments will launch between 6-17th November 2017, testing graphene in zero-gravity conditions to determine its potential in space applications.

Graphene Flagship aerospace experiments image

One of the two experiments (named GrapheneX) will be fully student-led, by a team of Graphene Flagship graduate students from Delft Technical University in the Netherlands. The team will use microgravity conditions in the ZARM Drop Tower (Bremen, Germany) to test graphene for light sails. By shining laser light on suspended graphene-membranes from Flagship partner Graphenea, the experiment will test how much thrust can be generated, which could lead to a new way of propelling satellites in space using light from lasers or the sun.