Researchers at the Massachusetts Institute of Technology, led by Associate Professor Yang Shao-Horn, in collaboration with Professor Paula Hammond, have found that using carbon nanotubes for one of the battery’s electrodes produced up to a tenfold increase in the amount of power that a lithiun-ion battery could deliver from a given weight of material.

In the new battery electrode, carbon nanotubes are "electrostatically self-assembled" into a tightly bound structure that is porous at the nanometer scale. The carbon nanotubes have many oxygen groups on their surfaces, which can store a large number of lithium ions. This enables carbon nanotubes to serve as the positive electrode in lithium batteries.

Carbon nanotubes are a form of pure carbon in which sheets of carbon atoms are rolled up into tiny tubes. Normally, carbon nanotubes on a surface tend to clump together in bundles, leaving few exposed surfaces to undergo reactions. The "electrostatic self-assembly" process incorporates organic molecules on the nanotubes and they assemble in a way that has a many exposed surfaces.

The new batteries have some of the advantages of both capacitors and conventional lithium batteries. Like capacitors, they can produce very high power outputs in short bursts - but the energy output for a given weight of the new electrode material is five times greater than for conventional capacitors. Like conventional batteries, they can provide lower power steadily for long periods - but the total power delivery rate with the new batteries is10  times that of lithium-ion batteries

In addition to their high power output, the carbon nanotube electrodes showed very good stability over time. After 1,000 cycles of charging and discharging a test battery, there was no detectable change in the material’s performance.

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Physicists at Boston College have developed a nano-scale solar cell, inspired by the coaxial cable, which offers greater efficiency than any previously designed nanotech thin film solar cell

A limiting factor in making highly efficient thin film sollar cells is the need for the cells to be thick enough to collect a sufficient amount of light, yet thin enough to extract current. The Boston College researchers have found a way to resolve this challenge using a coaxial design for cells constructed with amorphous, rather than crystalline, silicon

The researchers say that the nanocoax cells yield power conversion efficiency in excess of 8 percent, which is higher than any nanostructured thin film solar cell to date.

"Many groups around the world are working on nanowire-type solar cells, most using crystalline semiconductors," said Michael Naughton, a professor of physics at Boston College. "This nanocoax cell architecture, on the other hand, does not require crystalline materials, and therefore offers promise for lower-cost solar power with ultrathin absorbers. With continued optimization, efficiencies beyond anything achieved in conventional planar architectures may be possible, while using smaller quantities of less costly material."

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A team of MIT Biological Material Group researchers has developed a way of using a modified virus as a kind of biological scaffold that can assemble the nanoscale components needed to split a water molecule into hydrogen and oxygen atoms.

During photosynthesis in plant cells, natural pigments absorb sunlight, while catalysts then promote the use of that energy to split water into its component hydrogen and oxygen molecules.

The MIT team, led by Professor Angela Belcher, engineered a common, harmless bacterial virus called M13 so that it would attract and bind with molecules of  a biological pigment (in this case zinc porphyrins) and a catalyst (iridium oxide). The virus acts as a kind of scaffolding, causing the pigments and catalysts to line up with the right spacing to trigger the water-splitting reaction.

Using the virus to make the system assemble itself improves the efficiency of the oxygen production fourfold.
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Researchers at the Fraunhofer Institute in Bremen have developed a paint which they say improves the efficiency of ships, aircraft and wind turbines by reducing their flow resistance.

They have achieved this by modelling the paint’s structure on the scales of fast-swimnming sharks which evolved in a manner that significantly diminishes drag.

Carribean Reef Sharl (Image by Albert Kok via Wikimedia)

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Researchers led by Jongyoon Han at the Massachusetts Institute of Technology have developed a nanotechnology device able to extract salt from seawater, paving the way for small-scale desalination for drought regions and disaster zones.

Conventional desalination works by forcing water through a membrane to remove molecules of salt. This process requires a lot of energy and maintenance of the membrane. As a result, conventional desalination plants are big and expensive.

The new nanotechnology device works by a process called "ion concentration polarisation". A current of charged ions is passed through an ion-selective membrane. This creates a force which moves charged ions and particles in the water away from the membrane. Salt ions and any impurities get pushed to the side. This saltier water is then drawn off, leaving only de-salinated water.

The energy efficiency of the process is comparable to a large-scale desalination plant but small to medium scale, and even battery-power, desalination devices are feasible.

The costs of scaling up the process have not yet been determined but overheads should be lower than in conventional plants because gravity, rather than pumps, can be used to feed the water and because there is less of a problem with membrane fouling.

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Scientists at the University of East Anglia, led by Professor Thomas Nann, have reported a breakthrough in the production of hydrogen from water using the energy of sunlight.

Hydrogen is obtained from water by electrolysis. But, because the efficiency of the process is typically only between 20 and 40%, using a solar photovoltaic process to generate the necessary electricity uses more energy than is stored in the hydrogen which is produced.

The East Anglia team have found a way to increase the efficiency of the process to 60% or more, which could make it cost-effective.

They achieved this by using gold electrodes coated with nanoclusters of indium phosphide, which are up to 400 times more likely to absorb incoming photons than current electrodes. The nanoparticle-coated  electrodes are also much more durable than alternatives.

The scientists are now investigating the possibility of using alternative, cheaper materials than gold for the electrodes.

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Researchers from Imperial College London and their partners, including Volvo Car Corporation, are developing a prototype material which can store and discharge electrical energy and which is also strong and lightweight enough to be used for car parts.

Ultimately, they expect that the material, which is made of carbon fibre and a polymer resin, could be used in electric vehicles to make them lighter, more compact and more energy efficient. In addition, the researchers believe that the material could potentially be used for the casings of many everyday objects such as mobile phones and computers, so that they would not need a separate battery.

The researchers say that the material will store and discharge large amounts of energy much more quickly than conventional batteries. Furthermore, the recharging process causes little degradation in the composite material, because it does not involve a chemical reaction, whereas conventional batteries degrade over time.

The project co-ordinator, Dr Emile Greenhalgh, from the Department of Aeronautics at Imperial College London, says that “We are really excited about the potential of this new technology. We think the car of the future could be drawing power from its roof, its bonnet or even the door, thanks to our new composite material. Even the Sat Nav could be powered by its own casing. The future applications for this material don’t stop there – you might have a mobile phone that is as thin as a credit card because it no longer needs a bulky battery, or a laptop that can draw energy from its casing so it can run for a longer time without recharging. We’re at the first stage of this project and there is a long way to go, but we think our composite material shows real promise.”

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UCLA graduate student Hexian Deng and biochemistry professor Omar M. Yaghi, have developed synthetic crystals that can be used to trap carbon dioxide. Their “designer crystal” approach opens the door for low cost, scalable applications, such as trapping carbon dioxide from factories or vehicle exhaust pipes.

The new synthetic crystals can code information, just as DNA does, but in a more simple form based on the sequence of pores in the material. The result is a material with a sponge-like ability to trap gasses with a high degree of selectivity that results in highly efficient carbon capture. The researchers claim that they were able to achieve a 400% improvement in carbon dioxide capture by manipulating the sequence.

Professor Yaghi said that "What we think this will be important for is potentially getting to a viable carbon dioxide–capture material with ultra-high selectivity… I am optimistic that is within our reach. Potentially, we could create a material that can convert carbon dioxide into a fuel, or a material that can separate carbon dioxide with greater efficiency."

Other researchers are studying different carbon-capturing crystals such as zeolite, which is being investigated by Australia’’s CO2CRC.

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Scientists at Northwestern University in Chicago have developed a new material which permanently traps only the radioactive ion cesium and not other harmless ions like sodium.

The material is made from layers of a gallium, sulfur and antimony compound. It has been found to be extremely effective in removing radioactive cesium - which found in nuclear waste but is very difficult to clean up - from a sodium-rich solution, similar to real liquid nuclear waste. The cesium triggers a structural change in the material, causing it to snap its pores shut, like a venus flytrap, and trap the cesium ions within. The material sequesters 100 percent of the cesium ions from the solution while ignoring all of the sodium ions.

The research was described in an article in the Nature Chemistry journal. The paper’s senior author, Mercouri G. Kanatzidis, Professor of Chemistry in the Weinberg College of Arts and Sciences commented that "Seeing the windows close was completely unexpected, We expected ion exchange — we didn’t expect the material to respond dynamically. This gives us a new mechanism to focus on….A new class of materials that takes advantage of the flytrap mechanism could lead to a much-needed breakthrough in nuclear waste remediation."

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Engineers at Princeton University, led by Professor Michael McAlpine, have developed a power-generating rubber film which could harness natural body movements such as breathing and walking, to power pacemakers, mobile phones and other electronic devices. For example, shoes made of the material could harvest the pounding of walking and running to power mobile electrical devices.

The material is composed of ceramic nanoribbons embedded into silicone rubber sheets. The nanoribbons are made of lead zirconate titanate, a ceramic material that generates an electrical voltage when pressure is applied to it  The silicone sheets, with embedded nanoribbons,  generate electricity when flexed and are highly efficient at converting mechanical energy to electrical energy.

Because the silicone is biocompatible (it is already used for cosmetic implants and medical devices), it can be implanted in the body to power medical devices. Placed against the lungs, sheets of the material could use breathing motions to power pacemakers, obviating the current need for surgical replacement of the batteries to power the devices.

As well as generating electricity when it is flexed, the material flexes when electrical current is applied to it. This opens the door to other kinds of applications, such as use for microsurgical devices.

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