Carbon nanoballs can greatly contribute to sustainable energy supply

Researchers at Chalmers University of Technology have discovered that the insulation plastic used in high-voltage cables can withstand a 26 per cent higher voltage if nanometer-sized carbon balls are added. This could result in enormous efficiency gains in the power grids of the future, which are needed to achieve a sustainable energy system. The renewable energy sources of tomorrow will often be found far away from the end user. Wind turbines, for example, are most effective when placed out at sea. Solar energy will have the greatest impact on the European energy system if focus is on transport of solar power from North Africa and Southern Europe to Northern Europe. "Reducing energy losses during electric power transmission is one of the most important factors for the energy systems of the future," says Chalmers researcher Christian Müller. "The other two are development of renewable energy sources and technologies for energy storage." Together with colleagues from Chalmers University of Technology and the company Borealis in Sweden, he has found a powerful method for reducing energy losses in alternating current cables. The results were recently published in ("A New Application Area for Fullerenes: Voltage Stabilizers for Power Cable Insulation"). The researchers have shown that different variants of the C60 carbon ball, a nanomaterial in the fullerene molecular group, provide strong protection against breakdown of the insulation plastic used in high-voltage cables. Today the voltage in the cables has to be limited to prevent the insulation layer from getting damaged. The higher the voltage the more electrons can leak out into the insulation material, a process which leads to breakdown. It is sufficient to add very small amounts of fullerene to the insulation plastic for it to withstand a voltage that is 26 per cent higher, without the material breaking down, than the voltage that plastic without the additive can withstand. "Being able to increase the voltage to this extent would result in enormous efficiency gains in power transmission all over the world," says Christian Müller. "A major issue in the industry is how transmission efficiency can be improved without making the power cables thicker, since they are already very heavy and difficult to handle." Using additives to protect the insulation plastic has been a known concept since the 1970s, but until now it has been unknown exactly what and how much to add. Consequently, additives are currently not used at all for the purpose, and the insulation material is manufactured with the highest possible degree of chemical purity. In recent years, other researchers have experimented with fullerenes in the electrically conductive parts of high-voltage cables. Until now, though, it has been unknown that the substance can be beneficial for the insulation material. The Chalmers researchers have now demonstrated that fullerenes are the best voltage stabilizers identified for insulation plastic thus far. This means they have a hitherto unsurpassed ability to capture electrons and thus protect other molecules from being destroyed by the electrons. To arrive at these findings, the researchers tested a number of molecules that are also used within organic solar cell research at Chalmers. The molecules were tested using several different methods, and were added to pieces of insulation plastic used for high-voltage cables. The pieces of plastic were then subjected to an increasing electric field until they crackled. Fullerenes turned out to be the type of additive that most effectively protects the insulation plastic. The next step involves testing the method on a large scale in complete high-voltage cables for alternating current. The researchers will also test the method in high-voltage cables for direct current, since direct current is more efficient than alternating current for power transmission over very long distances. Facts: Carbon ball C60 The C60 carbon ball is also called buckminsterfullerene. It consists of 60 carbon atoms that are placed so that the molecule resembles a nanometer-sized football. C60 is included in the fullerene molecular class. Fullerenes were discovered in 1985, which resulted in the Nobel Prize in Chemistry in 1996. They have unique electronic qualities and have been regarded as very promising material for several applications. Thus far, however, there have been few industrial usage areas. Fullerenes are one of the five forms of pure carbon that exist. The other four are graphite, graphene/carbon nanotubes, diamond and amorphous carbon, for example soot. Facts: Higher voltage results in more efficient electric power transmission If small amounts of fullerene are added to high-voltage cable insulation plastic, voltage can be increased by up to 26 per cent. This means the transmitted power also increases by up to 26 per cent, since the power = voltage multiplied by current. Energy loss in the form of heat, however, does not increase if the current is kept constant since heat losses primarily depend on current. Power transmission can thereby be increased by up to 26 per cent, at the same time that energy loss stays at the same level – an efficiency increase in electric power transmission. Facts about the research The research has been conducted by eight researchers at Chalmers University of Technology in Sweden, at the Department of Chemistry and Chemical Engineering and the Department of Materials and Manufacturing Technology, as well as a researcher at Borealis AB in Stenungsund, Sweden. Chalmers’ Areas of Advance Materials Science and Energy have been responsible for funding, as has Borealis AB.
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'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables

New battery technology from the University of Michigan should be able to prevent the kind of fires that grounded Boeing 787 Dreamliners in 2013. The innovation is an advanced barrier between the electrodes in a lithium-ion battery. Made with nanofibers extracted from Kevlar, the tough material in bulletproof vests, the barrier stifles the growth of metal tendrils that can become unwanted pathways for electrical current. A U-M team of researchers also founded Ann Arbor-based Elegus Technologies to bring this research from the lab to market. Mass production is expected to begin in the fourth quarter 2016. "Unlike other ultra strong materials such as carbon nanotubes, Kevlar is an insulator," said Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering. "This property is perfect for separators that need to prevent shorting between two electrodes." Lithium-ion batteries work by shuttling lithium ions from one electrode to the other. This creates a charge imbalance, and since electrons can't go through the membrane between the electrodes, they go through a circuit instead and do something useful on the way. But if the holes in the membrane are too big, the lithium atoms can build themselves into fern-like structures, called dendrites, which eventually poke through the membrane. If they reach the other electrode, the electrons have a path within the battery, shorting out the circuit. This is how the battery fires on the Boeing 787 are thought to have started. "The fern shape is particularly difficult to stop because of its nanoscale tip," said Siu On Tung, a graduate student in Kotov's lab, as well as chief technology officer at Elegus. "It was very important that the fibers formed smaller pores than the tip size." While the widths of pores in other membranes are a few hundred nanometers, or a few hundred-thousandths of a centimeter, the pores in the membrane developed at U-M are 15-to-20 nanometers across. They are large enough to let individual lithium ions pass, but small enough to block the 20-to-50-nanometer tips of the fern-structures. The researchers made the membrane by layering the fibers on top of each other in thin sheets. This method keeps the chain-like molecules in the plastic stretched out, which is important for good lithium-ion conductivity between the electrodes, Tung said. "The special feature of this material is we can make it very thin, so we can get more energy into the same battery cell size, or we can shrink the cell size," said Dan VanderLey, an engineer who helped found Elegus through U-M's Master of Entrepreneurship program. "We've seen a lot of interest from people looking to make thinner products." Thirty companies have requested samples of the material. Kevlar's heat resistance could also lead to safer batteries as the membrane stands a better chance of surviving a fire than most membranes currently in use. While the team is satisfied with the membrane's ability to block the lithium dendrites, they are currently looking for ways to improve the flow of loose lithium ions so that batteries can charge and release their energy more quickly. The study, "A dendrite-suppressing solid ion conductor from aramid nanofibers," will appear online Jan. 27 in .
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Peptide nanoparticle delivery of oligonucleotide drugs into cells

Therapeutic oligonucleotide analogs represent a new and promising family of drugs that act on nucleic acid targets such as RNA or DNA; however, their effectiveness has been limited due to difficulty crossing the cell membrane. A new delivery approach based on cell-penetrating peptide nanoparticles can efficiently transport charge-neutral oligonucleotide analogs into cells, as reported in . The article is available free on the website. In the article, "Peptide Nanoparticle Delivery of Charge-Neutral Splice-Switching Morpholino Oligonucleotides", Peter Järver and coauthors, Cambridge Biomedical Campus (U.K.), Karolinska University Hospital (Huddinge, Sweden), Stockholm University (Sweden), Alexandria University (Egypt), and University of Oxford (U.K.), note that while delivery systems exist to facilitate cell entry of negatively charged oligonucleotide drugs, these approaches are not effective for charge-neutral oligonucleotide analogs. The authors describe lipid-functionalized peptides that form a complex with charge-neutral morpholino oligonucleotides, enabling them to cross into cells and retain their biological activity. "The exploitation of phosphorodiamidate morpholinos represents an exciting approach to treating a number of therapeutic targets," says Executive Editor Graham C. Parker, PhD, The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Children's Hospital of Michigan, Detroit, MI. "This paper suggests an intriguing but practical approach to solving the lack of a convenient non-covalent delivery system."
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