Fuel Cells - Page 5

Researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a battery-like hydrogen fuel cell, which surrounds hydrogen-absorbing magnesium nanocrystals with graphene oxide sheets to improve its performance.

The graphene shields the nanocrystals from oxygen, moisture and contaminants, while tiny, natural holes allow the smaller hydrogen molecules to pass through. This filtering process overcomes common problems degrading the performance of metal hydrids for hydrogen storage. The graphene-encapsulated magnesium crystals act as "sponges" for hydrogen, offering a very compact and safe way to take in and store hydrogen. The nanocrystals also permit faster fueling, and reduce the overall size.

A team of researchers at Kyushu University's International Institute for Carbon-Neutral Energy Research (I2CNER) designed a method that could prove a real breakthrough technology for fuel cells - by showing how wrapping a graphene support in a specially prepared polymer provides an excellent foundation for making uniform, highly active gold nanoparticle catalysts.

Gold nanoparticles have been recognized as an agreeable solution for improving the performance of catalysts that could be used in fuel cells, but creating a uniform, useful catalyst still remained elusive. However, the team in this study devised a method for using a new type of catalyst support. By wrapping the support in the polymer that was developed, the scientists created a much better support environment for the gold nanoparticles.

Researchers at the Ulsan National Institute of Science and Technology (UNIST) announced the development of an iron-carbon composite catalyst that can contribute to a reduction in the costs of fuel cells and Li-air batteries. 

The carbon composite catalyst contains iron and nitrogen and uses a graphene nanoplate. It is reportedly better than existing carbon catalysts in terms of durability and performance, and allows mass production at a low cost. The researchers hope that it will be able to contribute to the commercialization of metal-air batteries.

Scientists at Rice University and colleagues at the Chinese Academy of Sciences, the University of Texas at San Antonio and the University of Houston have reported the development of a graphene-based robust, solid-state catalyst that shows promise to replace expensive platinum for hydrogen generation.

The researchers have shown that graphene, doped with nitrogen and augmented with cobalt atoms, is an effective and durable catalyst for the production of hydrogen from water. This could be used in fuel cells, among other applications. 

Researchers at MIT and Lawrence Berkeley National Laboratory have developed a novel kind of tunable catalyst that could potentially replace costly rare metals that are currently used in fuel cells. The catalyst is made of graphite, with additional compounds attached to the edges of the 2D sheets of graphene that the material is composed of. The catalyst’s characteristics can be tuned to promote specific chemical reactions by altering the composition and the quantities of the additional compounds.

The scientists aimed at merging the attributes of two different electrocatalysts - Molecular electrocatalysts, that can be tuned through chemical treatment so their selectivity and reactivity can be customized, and heterogeneous electrocatalysts that can't be tuned precisely but are known for their durability and ease of processing into a device. The team worked towards chemically modifying graphite’s structure to provide the desired tunability.

The newly established Edison Motor Cars, a partnership between Sunvault Energy, the Edison Power Company and Delaware Corporation, has declared a highly ambitious first project: an electric car powered by graphene-based hydrogen fuel cell that will allegedly perform better than a Ferrari.

The car, to be named Edison Electron One, is meant to be unveiled in 2016 and equipped with an electric drive unit at each wheel, providing the vehicle with 1,355 Newton meters of torque (which is almost double that of a Ferrari 488 GTB and one third more than that of the Tesla P85D). The car will also be able to accelerate from zero to 100 km/h in about two seconds and recharge in five minutes.

Scientists from Rice University have managed to embed metallic nanoparticles into their previously-developed LIG (laser-induced graphene, a flexible film with a surface of porous graphene made by exposing a common plastic to a commercial laser-scribing beam), that turn the material into a catalyst for fuel cells and various other applications.

The researchers have now found a way to enhance the product with reactive metals and turn it into "metal oxide-laser induced graphene" (MO-LIG), a new candidate to replace expensive metals like platinum in catalytic fuel-cell applications in which oxygen and hydrogen are converted to water and electricity. The scientists state that a major advantage of this process is that commercial polymers can be used, with the addition of inexpensive metal salts. They are then subjected to the laser scriber, which generates metal nanoparticles embedded in graphene. In effect, the laser generates graphene in the open air at room temperature.

Researchers at the Korean Institute of Energy Research (KIER) and the University of Oxford in the UK showed that encapsulating platinum nanoparticles with nitrogen-doped graphene layers improves the catalytic activity of the particles, while making them more resistant to degradation. This could lead to better proton exchange membrane fuel cells (PEMFCs) in the future.

The scientists state that without the nitrogen treatment, the Ptgraphene nanoparticle is very resilient to degradation, but it also becomes a rather ineffective catalyst. The nitrogen treatment appears to 'puncture' the graphene shell, allowing the Pt underneath to catalyze reactions while being protected from the acidic electrolyte in a fuel cell. The researchers found that the porous graphene encapsulated Pt nanoparticles were almost as good as bare Pt nanoparticles in terms of catalytic performance (with a peak efficiency of 87% compared to bare Pt) but that they did not degrade compared to the bare particles.

A collaboration of scientists from several institutions, including Northwestern, EFRC and more, discovered that graphene that is slightly imperfect can shuttle protons from one side of a graphene membrane to the other in seconds. The selectivity and speed of the imperfect version are compared to conventional membranes, opening the door to new and simpler model of fuel cell designs.

This, of course, goes against conventional efforts to create perfect graphene as it turns out that protons move better through imperfect graphene. The defects in the graphene trigger a chemical "conveyor belt" that shuttles protons from one side of the membrane to the other in a few seconds. In conventional membranes, which can be hundreds of nanometers thick, the desired proton selection takes minutes, compared to the quick transfer in a one-atom-thick layer of graphene.

A study conducted at Rice University shows that graphene nanoribbons, formed into a 3D aerogel and enhanced with boron and nitrogen, perform extremely well as catalysts for fuel cells and may even pose an alternative to platinum.

The scientists chemically unzipped carbon nanotubes into ribbons and then turned them into porous metal-free aerogels with various levels of boron and nitrogen, to test their electrochemical properties. It was found that the new material provides a wealth of active sites along the exposed edges for oxygen reduction reactions necessary for fuel cells performance.