Reduced graphene oxide: an introduction - Page 7

Researchers at the Harbin Institute of Technology in China and the University of Michigan in the US demonstrated improved LFP battery cathode, augmented by reduced graphene oxide. The scientists used reduced graphene oxide (rGO) in LFP battery cathodes to create a new high surface area 3D composite.

LFP (or LiFePO4) is a kind of Li-Ion rechargeable battery for high power applications, such as electric vehicls, Power Tools and more. LFP cells feature high discharging current, non explosive nature and long cycle life, but its energy density is lower than normal Li-Ion cell. In this study, the researchers created the composite using a nickel foam template that was coated with layers of graphene oxide. The graphene oxide reduced as the LFP nanoparticles were synthesized in a simple technique that allows larger amounts of the LFP to be loaded into the carbon material.

Researchers at Australia's Swinburn University of Technology designed a graphene-based technique to create a 3D pop-up floating display. The scientists created nanoscale pixels of refractive index (the measure of the bending of light as it passes through a medium) made of reduced graphene oxide in a process that does not involve heat, which they say is important for the subsequent recording of the individual pixels for holograms and naked-eye 3D viewing.

The team explains that by changing the refractive index, it is possible to create many optical effects. This new technique can be leveraged to achieve compact and versatile optical components for controlling light and can create the wide-angle display necessary for mobile phones and tablets. The scientists believe that this new generation digital holographic 3D display technology could also have applications for military devices, entertainment, remote education, and medical diagnosis as well as lay foundation for future flexible and wearable display devices and transform them for 3D display.

Scientists at the Indian Institute of Engineering Science and Technology (IIEST) discovered that reduced graphene oxide (rGO) can be used in a unique sensor to detect a deadly cancer-causing food toxin with high sensitivity.

The toxin, Aflatoxin B1, is a common contaminant in peanuts, chillies, cottonseed meal, corn, rice and other grains. Produced by a fungus, it is a potent liver carcinogen that damages the immune system in humans and animals.

Researchers from the Bourns College of Engineering at the University of California, Riverside investigated a strategy to improve lithium-sulfur batteries' performance by creating nano-sized sulfur particles, and coating them in glass.

Lithium-sulfur batteries have been attracting attention thanks to their ability to produce up to 10 times more energy than conventional batteries, but one of the main roadblocks to implementing them is a the tendency for lithium and sulfur reaction products (called lithium polysulfides) to dissolve in the battery’s electrolyte and travel to the opposite electrode permanently, which causes the battery’s capacity to decrease over its lifetime. The scientists designed a cathode material in which silica (glass) cages trap polysulfides.. The team used an organic precursor to construct the trapping barrier.

University of Central Florida spin-off Garmor will take part in the NPE2015 Startup Garage and showcase its low-cost graphene oxide and reduced graphene oxide in addition to products made with graphene oxide polymer and fiberglass composites that can be used in a variety of applications ranging from automotive, aerospace, and military to consumer electronics, medical, and construction.

The company will also share the methods developed for the smooth dispersion of graphene into both polar and non-polar plastics. According to Garmor, the company’s partnership with the University of Central Florida (UCF) has played an integral role in perfecting a method to optimize the incorporation of graphene in various polymers, composite materials and coating.

Researchers at the Centre for Advanced Structural Ceramics at Imperial College London (ICL) cooperated with teams from the University of Warwick, the University of Bath, and the Universidad de Santiago de Compostela to use graphene oxide (GO) and reduced graphene oxide (rGO) together with small amounts of a responsive polymer (a polymer that changes upon activation of a 'chemical switch'), to formulate water based ink or pastes for 3D printing applications.

The scientists say that their formulations sport the required flow and physical properties for 3D printing (namely, the ability to flow through miniature nozzles but set immediately after that), for a technique called direct ink writing (DIW), robocasting or direct write assembly (DWA). This technique is based on the continuous deposition of a filament following a computer design.

The Spanish Graphenea collaborated with researchers from the French CNRS and SENSIA SL to design a graphene-based biosensor and develop a graphene-based method to destroy harmful bacteria.

The researchers studied the possibility to kill E. coli pathogens using reduced graphene oxide (rGO-PEG-NH2) and Au nanorods (Nrs) coated with rGO-PEG-NH2 by laser irradiation. The encapsulation of Au NRs with rGO-PEG not only decreases the toxicity of Au NRs, but also enhances the overall photothermal process and thus the temperatures which can be reached. 99% killing efficiency of bacteria was demonstrated in a water solution, at low concentrations (20-49 mg/ml).

Researchers from Nanyang Technological University in Singapore tested different graphene platforms for the detection of caffeine in samples. The ability of analysis of food components is crucial for various food safety applications.

The researchers compared the performances of graphite oxide (GPO), graphene oxide (GO), and electrochemically reduced graphene oxide (ERGO) for caffeine detection. ERGO performed best and showed lower oxidation potential, sensitivity, linearity and reproducibility of the response. ERGO managed to test caffeine levels of soluble coffee, teas and energetic drinks were measured without the need of any sample pre-treatment.

Researchers from Kansas State University studied graphene oxide sheets as flexible paper electrodes for sodium-ion flexible batteries and found GO to have important properties that can boost the efficiency of such batteries.

The scientists explored graphene oxide sheets as flexible paper electrodes for sodium batteries. They found that sodium storage capacity of paper electrodes depends on the distance between the layers that can be adjusted by heating it in argon or ammonia gas. The researchers also showed that a flexible paper composed entirely of graphene oxide sheets can charge and discharge with sodium-ions for more than 1,000 cycles.

Researchers from the Korea Electrotechnology Research Institue (KERI) managed to create an innovative process of 3D printing graphene nanostructures.

The scientists announced the development of a nanoscale 3D printing approach that exploits a liquid meniscus of ink to create 3D reduced graphene oxide (rGO) nanowires, different than typical methods that use filaments or powders as printing materials.