Fuel Cells - Page 4

Rice University scientists have attached ruthenium atoms to graphene to create a durable catalyst for high-performance fuel cells. Most catalysts used to drive the oxygen reduction reaction that lets fuel cells turn chemical energy into electricity are made of platinum, which stands up to the acidic nature of the cell’s charge-carrying electrolyte. However, platinum is expensive, and replacements have long been searched for by researchers.

The ruthenium-graphene combination may pose a suitable replacement; In tests, its performance was said to easily match that of traditional platinum-based alloys and bested iron and nitrogen-doped graphene, another contender.

Researchers from the University of Arkansas have tackled the issue of graphene oxide's flammability; The team explains that scaling up the production of graphene-based materials is often problematic and dangerous due to GO's tendency to become explosive once airborne, so solving this problem may prove important.

In their work, the team established a relatively simple method to cross-link GO with Al3+ cations, in one step, into a freestanding flexible membrane. This membrane resists in-air burning on an open flame, at which non-cross-linked GO was burnt out within ∼5 s. With the improved thermal and water stabilities, the cross-linked GO film can help advance high-temperature fuel cells, electronic packaging, etc.

Prof. James Tour's research lab in Rice University is one of the leading graphene research groups in the world, with several key technologies first discovered and developed there. Professor Tour is involved with several application areas - from de-icing coating to energy storage and quantum dots production. Prof. Tour was kind enough to share his time and update us on the latest research and commercialization efforts at his lab.

The Tour group is now commercializing two of its key technologies. First up is the laser-induced graphene (or LiG), which was reported first in 2014. This is a process in which graphene is formed on a flexible polyimide film using a room-temperature laser-based process. It is possible to pattern this graphene to create devices and as it is formed on a flexible film this easily enables flexible electronics applications.

UK-based Haydale announced its unaudited results for the six months ended 31 December 2016, or H1 FY2016. Total income was £1.5 million (up 90% from H1 2015) and the loss was £2.4 million (up from £1.9 million in H1 2015).

Haydale also provided some interesting update. The company signed a joint development agreement with Hunsman in Novermber 2016, and Haydale now says that Huntsman announced strong initial test results from Haydale's graphene enhanced Araldite resins in thermal management. Haydale's Thailand subsidiary also announced two new small contacts - one from the Thai Ministry of Energy for a printed hybrid functionalized graphene electrode in a supercapacitor and another from IRPC, a leading Thai petrochemical chemical processor.

Grafoid, a leading graphene R&D and investment company, announced its entry into the global industrial coatings market with the introduction of its patent pending GrafeneX graphene coatings technology. Grafoid describes the GrafeneX technologies as a cost-effective way of laying down graphene coatings on large surface areas.

GrafeneX is a novel technology that creates a platform for the deposition of graphene and chemically functionalized graphene coatings. This process provides Grafoid with the capability to apply its diverse graphene-based coatings to many different types of material substrates with controllable levels of surface coverage, thickness etc. to meet precise end user requirements.

Researchers at The University of Manchester, UK, have tested graphene and hexagonal boron nitride (hBN) in the membrane area of fuel cell. The reported results show a rather exciting reduction in crossover (diffusion of methanol from anode to cathode through the membrane that causes short-circuits) with no changes in proton conductivity and a performance improvement of up to 50%.

Fuel cells, devices that convert the chemical energy of fuel directly into electrical energy through oxidation-reduction reactions, are considered to have potential for use in future energy applications as they are efficient and clean. Methanol fuel cells are widely favored due to their usage of methnaol as a liquid fuel, simplicity in operation, higher energy density of methnaol fuel and more. A major hindrance to commercialization,though, is methanol crossover taking place in the membrane area of fuel cells, leading to short circuits and greatly affecting overall performance.

Researchers at Rice University have found that layers of graphene, separated by nanotube pillars of boron nitride, may be a suitable material to store hydrogen fuel in cars. The boron nitride pillars are situated between graphene layers to make space for hydrogen atoms, similarly to spaces between floors in a building. The actual challenge is to make the atoms enter and stay in sufficient numbers and exit upon demand.

In their latest molecular dynamics simulations, the researchers found that either pillared graphene or pillared boron nitride graphene would offer abundant surface area (about 2,547 square meters per gram) with good recyclable properties under ambient conditions. Their models showed adding oxygen or lithium to the materials would make them even better at binding hydrogen.

Garmor, a graphene technology provider and developer of advanced customer-driven applications, has developed graphene-based composites ideal for high-volume electronic and energy storage applications. By leveraging inexpensive manufacturing methods to produce few-layer graphene oxide (GO) along with innovative composite compression molding processes, Garmor produced compression-moldable GO-composites that can be shaped and stamped into almost any form factor. Garmor is currently establishing strategic business relationships to deploy this technological advancement in applications focused on energy production and storage.

These composites exhibit nearly isotropic electrical conductivity exceeding 1,000 S/cm delivering a unique, omnidirectional conductive substrate. Equally impressive is that these GO-enhanced materials include a polymeric resin that is inherently chemically resistant and allows for increased lifetime even in harsh operating environments.

A research team at Los Alamos, along with collaborators from Oak Ridge National Laboratory, the University of New Mexico, and Rutgers University, has developed a new water-removal technique that improves the performance of carbon nanomaterials used in fuel cells and batteries. The study may present new avenues for designing advanced carbon nanomaterials for batteries and fuel cells.

The study gives an in-depth understanding of the role water plays in graphene oxide nanosheets or functionalized graphene sheets. Dry films of graphene oxide include a significant volume of added water that builds up between the oxygen-functionalized nanosheets and is also usually produced in aqueous solutions. The researchers showed how a simple solvent drying method can remove the accumulated water between the graphitic sheets. When water is removed, the physical structure of these graphene oxide nanosheets changes considerably, and the distance between the nanosheets is also reduced. In addition to this, the researchers also noted that the concentration of functional groups changed significantly, resulting in highly ordered structures. These changes ultimately led to improved electrocatalytic activity, which substantially improves the performance in batteries and fuel cells.

Researchers at Brown University have demonstrated that graphene, wrinkled and crumpled in a multi-step process, becomes significantly better at repelling water - a property that could be useful in making self-cleaning surfaces. Crumpled graphene also has enhanced electrochemical properties, which could make it more useful as electrodes in batteries and fuel cells.

The researchers aimed to build relatively complex architectures incorporating both wrinkles and crumples. To do that, the researchers deposited layers of graphene oxide onto shrink films -polymer membranes that shrink when heated. As the films shrink, the graphene on top is compressed, causing it to wrinkle and crumple. To see what kind of structures they could create, the researchers compressed same graphene sheets multiple times. After the first shrink, the film was dissolved away, and the graphene was placed in a new film to be shrunk again.