Carbon nanotubes and graphene - properties, applications and market - Page 2

A team of scientists from Harvard’s Wyss Institute and John A. Paulson School of Engineering and Applied Sciences (SEAS) has created flexible, metal-free electrode arrays that conform to the body. This conformity allows, for example, electrical impulses to be recorded and stimulated with lower required voltages, enabling their use in hard-to-reach areas of the body, and minimizes the risk of damage to delicate organs.

Arrays of metal electrodes are currently used in medical procedures that require monitoring or delivering electrical impulses in the body, such as brain surgery and epilepsy mapping. However, the metal and plastic materials that comprise them are stiff and inflexible while the body’s tissues are soft and malleable. This mismatch limits the places in which electrode arrays can be successfully used, and also requires the application of a large amount of electrical current in order to jump the gap between an electrode and its target. In this new work, the team tackles this issue and delivers soft and conformable graphene and CNTs based electrodes.

CPI and Thomas Swan have teamed up with Johnson Matthey (JM), a company focused on sustainable technologies, to explore how to best optimize battery technology using graphene and CNTs.

The ICE-Batt project receives funding support from the Faraday Battery Challenge, managed by Innovate UK the UK’s innovation agency to enable the investigation of how innovative carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) can improve battery performance. In addition, the project will explore how to improve the green credentials of battery processing.

Researchers at Duke University have created transistors with three carbon-based inks. The all-carbon thin-film transistors were made using crystalline nanocellulose as a dielectric, carbon nanotubes as a semiconductor, graphene as a conductor and paper as a substrate. This type of component could assist in addressing the environmental problem of accumulation of electronics that are non-recyclable.

Silicon-based computer components are probably never going away and we don’t expect easily recyclable electronics like ours to replace the technology and devices that are already widely used, said Professor Aaron Franklin, an electrical engineer at Duke University. But we hope that by creating new, fully recyclable, easily printed electronics and showing what they can do, that they might become widely used in future applications.

A research team from the Korea Institute of Science and Technology (KIST) recently developed a graphene-based lithium-ion battery that is flexible enough to be stretched.

Dr. Jeong Gon Son's research team at the Photo-Electronic Hybrids Research Center at the Korea Institute of Science and Technology (KIST) developed the high-capacity, stretchable lithium-ion battery. The battery was developed by fabricating a structurally stretchable electrode consisting solely of electrode materials and then assembling it with stretchable gel electrolyte and stretchable packaging.

Scientists in the Korea Institute of Science and Technology (KIST) have worked with graphene and carbon nanotubes to develop a working lithium-ion battery that can be stretched by up to 50% without damage to any of the components. According to the scientists, the battery represents a significant step in the development of wearable or body-implantable electronic devices.

Rather than trying to add inherently stretchable materials such as rubber to the battery components, the group focused on creating an accordion-like structure, adding stretchability to materials that are not inherently stretchable. Using graphene and carbon nanotubes, the scientists were able to construct a honeycomb-shaped composite framework, which was then compressed inwardly like an accordion to impart the stretchable properties.

Researchers at Aalto University, collaborating with researchers at CNRS France, have developed a graphene-carbon nanotube catalyst which gives better control over important chemical reactions for producing green technology and clean energy.

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the most important electrochemical reactions that limit the efficiencies of hydrogen fuel cells (for powering vehicles and power generation), water electrolyzers (for clean hydrogen production), and high-capacity metal-air batteries. The team has developed a new catalyst that reportedly drives these reactions more efficiently than other bifunctional catalysts currently available. The researchers also found that the electrocatalytic activity of their new catalyst can be significantly altered depending on choice of the material on which the catalyst was deposited.

Rice University scientists have developed a graphene-based epoxy for electronic applications. Epoxy combined with graphene foam invented in the Rice lab of Prof. James Tour) is reportedly substantially tougher than pure epoxy and far more conductive than other epoxy composites, while retaining the material's low density. It could improve upon epoxies in current use that weaken the material's structure with the addition of conductive fillers.

By itself, epoxy is an insulator, and is commonly used in coatings, adhesives, electronics, industrial tooling and structural composites. Metal or carbon fillers are often added for applications where conductivity is desired, like electromagnetic shielding. The trade-off, however, is that more filler brings better conductivity at the cost of weight and compressive strength, and the composite becomes harder to process. The Rice solution replaces metal or carbon powders with a 3D foam made of nanoscale sheets of graphene.

Rice University researchers have found that fracture-resistant rebar graphene is more than twice as tough as pristine graphene. While on the two-dimensional scale, graphene is stronger than steel, its extremely thin nature makes it subject to ripping and tearing. Rebar graphene is the nanoscale analog of rebar (reinforcement bars) in concrete, in which embedded steel bars enhance the material’s strength and durability. Rebar graphene, developed by the Rice lab of chemist James Tour in 2014, uses carbon nanotubes for reinforcement.

In a new study, Rice materials scientist Jun Lou, graduate student and lead author Emily Hacopian and collaborators, including Prof. James Tour, stress-tested rebar graphene and found that nanotube rebar diverted and bridged cracks that would otherwise propagate in unreinforced graphene.

First Graphene is collaborating with Flinders University to launch 2D Fluidics - a company that will aim to commercialize the Vortex Fluidic Device (VFD). 2D Fluidics is 50% owned by FGR and 50% by Flinders University’s newly named Flinders Institute for NanoScale Science and Technology.

The VFD was invented by the Flinders Institute for NanoScale Science and Technology’s Professor Colin Raston and enables new approaches to producing a wide range of materials such as graphene and sliced carbon nanotubes. The key intellectual property used by 2D Fluidics comprises two patents around the production of carbon nanomaterials, assigned by Flinders University.

Researchers at Zhejiang University in China have designed a new type of aerogels, made of graphene and carbon nanotubes, that can be reversibly stretched to more than three times their original length, displaying elasticity similar to that of a rubber band. This stretchability, in addition to aerogels' existing properties like ultralow density, light weight, high porosity, and high conductivity, may lead to exciting new applications.

The scientists designed carbon aerogels consisting of both graphene and multi-walled carbon nanotubes assembled into four orders of hierarchical structures ranging from the nanometer to centimeter scale. To fabricate the material into aerogels, the researchers created an ink composed of graphene oxide and nanotubes, and then formed the aerogels via inkjet printing.