25-Sep-2020: Scientists of JNCASR of DST develop a new low cost method of upscaling most conductive material ‘graphene’ while preserving its single layered properties
Graphene, the one-atom-thick sheet of carbon atoms, which is a boon for energy storage, coatings, sensors as well as superconductivity, is difficult to produce while retaining its single layered properties.
A new low-cost method of upscaling production of graphene while preserving its single layered properties, developed by Indian scientists, may reduce the cost of producing this thinnest, strongest and most conductive material in the world.
Researchers from Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) an autonomous institute under the Department of Science & Technology, Government of India through their recent research work have upscaled graphene production while retaining its thin layered properties. This was made possible by a simple, affordable method wherein naphthalene coated nickel foil was heated for a few minutes in an ordinary vacuum by joule heating and was cooled to get twisted layers of graphene. Careful study using electronic diffraction and Raman scattering showed that the 2D single-crystal nature of the atomic lattice of the graphene is retained even in the multilayer stack. The twisted multilayer graphene that results is also highly conducting.
In the research by Nikita Gupta (Ph.D. student, JNCASR) and Prof. G.U. Kulkarni (corresponding author ) published in the ‘Journal of Physical Chemistry Letters’, the scientists have also defined a formula to quantify how much single layer like behaviour exists in such a system. The twisted system has multiple layers, each behaving like a single layer, allows variation in the experimental data within one sample, thus making quantification possible to achieve. The derived formula provides an insight into any twisted hexagonal multilayer system and may be used to tune superconductivity.
The researchers used a combination of two techniques to understand and quantify how much single layer like behaviour exists in the graphene system. Raman spectroscopy---a technique to understand whether a graphene species has single layer like behaviour arising because of no interlayer interaction and electron diffraction--a technique to study the morphology of the given twisted system.
Observing fascinating properties of twisted multilayer graphene such as visible absorption band, efficient corrosion resistance, temperature-dependent transport, influencing the crystalline orientation of source material, helped the JNCASR team to understand the landscape of the given twisted multilayer graphene system.
Recent publication in the journal ‘Nature’ by James M. Tour, an eminent peer on this research discovery (https://doi.org/10.1038/s41586-020-1938-0), confirms the upper limit of relative Raman intensity predicted by this work, experimentally. The present understanding of twisted multilayer graphene will help in understanding any twisted hexagonal system. It gives an upper limit of relative Raman intensity which can exist in a particular multilayer graphene system.
28-Nov-2017: Graphene based Battery Material with 5x Faster Charging Speed
Recently, a team of researchers at the Samsung Advanced Institute of Technology (SAIT) developed a “graphene ball,” a unique battery material that enables a 45% increase in capacity, and five times faster charging speeds than standard lithium-ion batteries. The breakthrough provides promise for the next generation secondary battery market, particularly related to mobile devices and electric vehicles. In its research, SAIT collaborated closely with Samsung SDI as well as a team from Seoul National University’s School of Chemical and Biological Engineering.
Lithium-ion batteries were first commercialized in 1991, and widely applied to markets for mobile devices and electric vehicles. However, with standard lithium batteries requiring charging times of at least an hour to fully charge, even with quick charging technology, and considered to have reached their limit for capacity expansion, there have been numerous attempts to explore use of new innovative materials. Among the materials looked at, graphene has widely become the primary source of interest as the representative next generation material.
In theory, a battery based on the “graphene ball” material requires only 12 minutes to fully charge. Additionally, the battery can maintain a highly stable 60 degree Celsius temperature, with stable battery temperatures particularly key for electric vehicles.
In its research, SAIT sought for an approach to apply graphene, a material with high strength and conductivity to batteries, and discovered a mechanism to mass synthesize graphene into a 3D form like popcorn using affordable silica (SiO2). This “graphene ball” was utilized for both the anode protective layer and cathode materials in lithium-ion batteries. This ensured an increase of charging capacity, decrease of charging time as well as stable temperatures.
Dr. Son In-hyuk, who led the project on behalf of SAIT, said, “Our research enables mass synthesis of multifunctional composite material graphene at an affordable price. At the same time, we were able to considerably enhance the capabilities of lithium-ion batteries in an environment where the markets for mobile devices and electric vehicles is growing rapidly. Our commitment is to continuously explore and develop secondary battery technology in light of these trends.”
17-Feb-2017: “Graph-Air” technology
Scientists have used soybean to make graphene commercially more viable. Graphene is a carbon material that is one atom thick. The potential applications of graphene include water filtration and purification, renewable energy, sensors, personalized healthcare and medicine etc... Its thin composition and high conductivity makes it apt for diverse applications ranging from miniature electronics to biomedical devices.
It's properties also enable thinner wire connections; providing extensive benefits for computers, solar panels, batteries, sensors and other devices. Until now, the high cost of graphene production has been the major roadblock in its commercialisation.
Previously, graphene was grown in a highly-controlled environment with explosive compressed gases, requiring long hours of operation at high temperatures and extensive vacuum processing. Scientists at Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia have developed a novel “Graph-Air” technology which eliminates the need for such highly-controlled environment.
The technology grows graphene film in ambient air with a natural precursor, making its production faster and simpler. This ambient-air process for graphene fabrication is fast, simple, safe, potentially scalable, and integration friendly.
Graph-Air transforms soybean oil – a renewable, natural material – into graphene films in a single step. Graph-Air technology results in good and transformable graphene properties, comparable to graphene made by conventional methods.
With heat, soybean oil breaks down into a range of carbon building units that are essential for the synthesis of graphene. The team also transformed other types of renewable and even waste oil, such as those leftover from barbecues or cooking, into graphene films.