Gilded fuel cells boost electric car efficiency

To make modern-day fuel cells less expensive and more powerful, a team led by Johns Hopkins chemical engineers has drawn inspiration from the ancient Egyptian tradition of gilding. Egyptian artists at the time of King Tutankhamun often covered cheaper metals (copper, for instance) with a thin layer of a gleaming precious metal such as gold to create extravagant masks and jewelry. In a modern-day twist, the Johns Hopkins-led researchers have applied a tiny coating of costly platinum just one nanometer thick—100,000 times thinner than a human hair—to a core of much cheaper cobalt. This microscopic marriage could become a crucial catalyst in new fuel cells that generate electric current to power cars and other machines.

The new fuel cell design would save money because it would require far less platinum, a very rare and expensive metal that is commonly used as a catalyst in present-day fuel-cell electric cars. The researchers, who published their work earlier this year in Nano Letters, say that by making electric cars more affordable, this innovation could curb the emission of carbon dioxide and other pollutants from gasoline– or diesel-powered vehicles.

This technique could accelerate our launch out of the fossil fuel era,” said Chao Wang, a Johns Hopkins assistant professor in the Department of Chemical and Biomolecular Engineering and senior author of the study. “It will not only reduce the cost of fuel cells. It will also improve the energy efficiency and power performance of clean electric vehicles powered by hydrogen.”

In their journal article, the authors tipped their hats to the ancient Egyptian artisans who used a similar plating technique to give copper masks and other metallic works of art a lustrous final coat of silver or gold.The idea,” Wang said, “is to put a little bit of the precious treasure on top of the cheap stuff.”

He pointed out that platinum, frequently used in jewelry, also is a critical material in modern industry. It catalyzes essential reactions in activities including petroleum processing, petrochemical synthesis, and emission control in combustion vehicles, and is used in fuel cells. But, he said, platinum’s high cost and limited availability have made its use in clean energy technologies largely impractical—until now.


Nanocomputer: Carbon Nanotube Transistors Outperform Silicon

For decades, scientists have tried to harness the unique properties of carbon nanotubes to create high-performance electronics that are faster or consume less power — resulting in longer battery life, faster wireless communication and faster processing speeds for devices like smartphones and laptops. But a number of challenges have impeded the development of high-performance transistors made of carbon nanotubes, tiny cylinders made of carbon just one atom thick. Consequently, their performance has lagged far behind semiconductors such as silicon and gallium arsenide used in computer chips and personal electronics.

Now, for the first time, University of Wisconsin–Madison materials engineers have created carbon nanotube transistors that outperform state-of-the-art silicon transistors. Led by Michael Arnold and Padma Gopalan, UW–Madison professors of materials science and engineering, the team’s carbon nanotube transistors achieved current that’s 1.9 times higher than silicon transistors. The researchers reported their advance in a paper published in the journal Science Advances.

carbon nanotube integrated circuits

This achievement has been a dream of nanotechnology for the last 20 years,” says Arnold. “Making carbon nanotube transistors that are better than silicon transistors is a big milestone. This breakthrough in carbon nanotube transistor performance is a critical advance toward exploiting carbon nanotubes in logic, high-speed communications, and other semiconductor electronics technologies.”

This advance could pave the way for carbon nanotube transistors to replace silicon transistors and continue delivering the performance gains the computer industry relies on and that consumers demand. The new transistors are particularly promising for wireless communications technologies that require a lot of current flowing across a relatively small area.


How To Scavenge Simultaneously Solar And Wind Energy

To realize the sustainable energy supply in a smart city, it is essential to maximize energy scavenging from the city environments for achieving the self-powered functions of some intelligent devices and sensors.

solar and wind powered houseAlthough the solar energy can be well harvested by using existing technologies, the large amounts of wasted wind energy in the city cannot be eectively utilized since conventional wind turbine generators can only be installed in remote areas due to their large volumes and safety issues.
Here, the researchers from the Chinese Academy of Sciences rationally design a hybridized nanogenerator, including a solar cell (SC) and a triboelectric nanogenerator (TENG), that can individually/simultaneously scavenge solar and wind energies, which can be extensively installed on the roofs of the city buildings. Under the same device area of about 120 mm × 22 mm, the SC can deliver a largest outputpower of about 8 mW, while the output power of the TENG can be up to 26 mW. Impedance matching between the SC and TENG has been achieved by using a transformer to decrease the impedance of the TENG. The hybridized nanogenerator has a larger output current and a better charging performance than that of the individual SC or TENG.
This research presents a feasible approach to maximize solar and wind energies scavenging from the city environments with the aim to realize some self-powered functions in smart city.


Living Power Cables

Electricity and seawater are usually a bad mix. And it was thus a very big surprise when scientists from Aarhus University – Denmark – a few years ago discovered electric currents between biological processes in the seabed. Since then they have been searching for an explanation and together with partners from the University of Southern California, USA, they have solved the enigma of electric currents in the seabed sensationally discovering bacteria that function as living electrical cables. Each of the centimetre-long ‘cable bacteria’ contains a bundle of insulated wires leading an electric current from one end to the other.

Our experiments showed that the electric connections in the seabed must be solid structures built by bacteria,” says PhD student Christian Pfeffer, Aarhus University.The bacterium is one hundred times thinner than a hair and the whole bacterium functions as an electric cable with a number of insulated wires within it. Quite similar to the electric cables we know from our daily lives. “Such unique insulated biological wires seem simple but with incredible complexity at nanoscale,” says PhD student Jie Song, Aarhus University, who used nanotools to map the electrical properties of the cable bacteria.