Electric Car: Nanofiber Electrodes Boost Fuel Cells By 30 Percent

At the same time Honda and Toyota are introducing fuel cell cars to the U.S. market, a team of researchers from Vanderbilt University, Nissan North America and Georgia Institute of Technology have teamed up to create a new technology designed to give fuel cells more oomph. The project is part of a $13 million Department of Energy program to advance fuel cell performance and durability and hydrogen storage technologies announced last month.

hydrogen fuel cells

Fuel cells were invented back in 1839 but their first real world application wasn’t until the 1960’s when NASA used them to power the Apollo spacecraft. Fuel cells need fuel and air to run, like a gasoline engine, but they produce electricity, like a battery. In hydrogen/air fuel cells, hydrogen flows into one side of the device. Air is pumped into the other side. At the anode, the hydrogen is oxidized into protons. The protons flow to the cathode where the air is channeled, reducing the oxygen to form water. Special catalysts in the anode and cathode allow these reactions to occur spontaneously, producing electricity in the process. Fuel cells convert fuel to electricity with efficiencies ranging from 40 percent to 60 percent. They have no moving parts so they are very quiet. With the only waste product being water, they are environmentally friendly.The $2.5 million collaboration is based on a new nanofiber mat technology developed by Peter Pintauro, Professor of Chemical Engineering at Vanderbilt, that replaces the conventional electrodes used in fuel cells. The nanofiber electrodes boost the power output of fuel cells by 30 percent while being less expensive and more durable than conventional catalyst layers. The technology has been patented by Vanderbilt and licensed to Merck KGaA in Germany, which is working with major auto manufacturers in applying it to the next generation of automotive fuel cells.

Conventional fuel cells use thin sheets of catalyst particles mixed with a polymer binder for the electrodes. The catalyst is typically platinum on carbon powder. The Vanderbilt approach replaces these solid sheets with mats made from a tangle of polymer fibers that are each a fraction of the thickness of a human hair made by a process called electrospinning. Particles of catalyst are bonded to the fibers. The very small diameter of the fibers means that there is a larger surface area of catalyst available for hydrogen and oxygen gas reactions during fuel cell operation. The pores between fibers in the mat electrode also facilitate the removal of the waste water. The unique fiber electrode structure results in higher fuel cell power, with less expensive platinum.
Source: http://news.vanderbilt.edu/

Green Electronics

A team of University of Toronto chemists has created a battery that stores energy in a biologically-derived unit, paving the way for cheaper consumer electronics that are easier on the environment.

The battery is similar to many commercially-available high-energy lithium-ion batteries with one important difference. It uses flavin from vitamin B2 as the cathode: the part that stores the electricity that is released when connected to a device.

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We’ve been looking to nature for a while to find complex molecules for use in a number of consumer electronics applications,” says Dwight Seferos, a professor in U of T’s department of chemistry and Canada Research Chair in Polymer Nanotechnology. “When you take something made by nature that is already complex, you end up spending less time making new material,” says Seferos.

The team created the material from vitamin B2 that originates in genetically-modified fungi using a semi-synthetic process to prepare the polymer by linking two flavin units to a long-chain molecule backbone. This allows for a green battery with high capacity and high voltage – something increasingly important as the ‘Internet of Things’ continues to link us together more and more through our battery-powered portable devices.

It’s a pretty safe, natural compound,” Seferos adds. “If you wanted to, you could actually eat the source material it comes from.” B2’s ability to be reduced and oxidized makes its well-suited for a lithium ion battery.

Source: https://www.utoronto.ca/

EV: A Thin Film That Produces Oxygen and Hydrogen

A cobalt-based thin film serves double duty as a new catalyst that produces both hydrogen and oxygen from water to feed fuel cells, according to scientists at Rice University. This discovery may lower the cost of future hydrogen electric car.  The inexpensive, highly porous material invented by the Rice lab of chemist James Tour may have advantages as a catalyst for the production of hydrogen via water electrolysis. A single film far thinner than a hair can be used as both the anode and cathode in an electrolysis device.

The researchers led by Rice postdoctoral researcher Yang Yang reported their discovery  in Advanced Materials.

They determined their cobalt film is much better at producing hydrogen than most state-of-the-art materials and is competitive with (and much cheaper than) commercial platinum catalysts. They reported the catalyst also produced an oxygen evolution reaction comparable to current materials.

CATALYST

A side view of a porous cobalt phosphide/phosphate thin film created at Rice University. The robust film could replace expensive metals like platinum in water-electrolysis devices that produce hydrogen and oxygen for fuel cells. The scale bar equals 500 nanometers.

It is amazing that in water-splitting, the same material can make both hydrogen and oxygen,” Tour said. “Usually materials make one or the other, but not both.”

The researchers suggested applying alternating current from wind or solar energy sources to cobalt-based electrolysis could be an environmentally friendly source of hydrogen and oxygen.

Source: http://news.rice.edu/

Electric Car: How To Increase the Batteries Life-Span

Drexel University (Philadephia) researchers, along with colleagues at Aix-Marseille University in France, have discovered a high performance cathode material with great promise for use in next generation lithium-sulfur batteries that could one day be used to power mobile devices and electric cars.

Lithium-sulfur batteries have recently become one of the hottest topics in the field of energy storage devices due to their high energy density — which is about four times higher than that of lithium-ion batteries currently used in mobile devices. One of the major challenges for the practical application of lithium-sulfur batteries is to find cathode materials that demonstrate long-term stability.

An international research collaboration led by Drexel’s Yury Gogotsi, PhD, professor in the College of Engineering and director of its Nanomaterials Research Group, has created a two-dimensional carbon/sulfur nanolaminate that could be a viable candidate for use as a lithium-sulfur cathode.
Tesla-Model-S One of the major challenges for the practical application of lithium-sulfur batteries is to find cathode materials that demonstrate long-term stability.

The carbon/sulfur nanolaminates synthesized by Gogotsi’s group demonstrate the same uniformity as the infiltrated carbon nanomaterials, but the sulfur in the nanolaminates is uniformly deposited in the carbon matrix as atomically thin layers and a strong covalent bonding between carbon and sulfur is observed. This may have a significant impact on increasing the life-span of next generation batteries.

In a paper they recently published in the chemistry journal Angewandte Chemie, Gogotsi, along with his colleagues at Aix-Marseille University explain their process for extracting the nanolaminate from a three-dimensional material called a Ti2SC MAX phase.
Source: http://drexel.edu

Boosted Lithium Sulfur Batteries For Electric Car

Lithium-sulfur batteries have been a hot topic in battery research because of their ability to produce up to 10 times more energy than conventional batteries, which means they hold great promise for applications in energy-demanding electric vehicles.
However, there have been fundamental road blocks to commercializing these sulfur batteries. One of the main problems is 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. This causes the battery’s capacity to decrease over its lifetime.
Researchers in the Bourns College of Engineering at the University of California, Riverside have investigated a strategy to prevent this “polysulfide shuttling” phenomenon by creating nano-sized sulfur particles, and coating them in silica (SiO2), otherwise known as glass.
Bourns College
Ph.D. students in Cengiz Ozkan’s and Mihri Ozkan ‘s research groups have been working on designing a cathode material in which silica cages “trap” polysulfides having a very thin shell of silica, and the particles’ polysulfide products now face a trapping barrier – a glass cage. The team used an organic precursor to construct the trapping barrier.

Our biggest challenge was to optimize the process to deposit SiO2 – not too thick, not too thin, about the thickness of a virus”, Mihri Ozkan said.
The work is outlined in the journal Nanoscale.
Source: http://ucrtoday.ucr.edu/

Li-Ion Batteries Mimick Shells To Last Longer

Scientists are using biology to improve the properties of lithium ion batteries. Researchers at the University of Maryland, Baltimore County (UMBC) have isolated a peptide, a type of biological molecule, which binds strongly to lithium manganese nickel oxide (LMNO), a material that can be used to make the cathode in high performance batteries. The peptide can latch onto nanosized particles of LMNO and connect them to conductive components of a battery electrode, improving the potential power and stability of the electrode.

snail_shell_battery-3
Biology provides several tools for us to solve important problems,” said Evgenia Barannikova, a graduate student at UMBC. Barannikova works in the lab of Mark Allen and studies how biological molecules in general can improve the properties of inorganic materials in batteries.

Biology provides several tools for us to solve important problems,” said Evgenia Barannikova, a graduate student at UMBC. Barannikova works in the lab of Mark Allen and studies how biological molecules in general can improve the properties of inorganic materials in batteries.
By providing a new nanoscale architecture for lithium-ion batteries, the researchers say that the approach could improve the power and cycling stability of lithium-ion batteries.
The researchers will present their results at the 59th annual meeting of the Biophysical Society, held Feb. 7-11 in Baltimore, Maryland.
Source: http://phys.org/