Using unique design and building methods, researchers have created a prototype for an ultra-thin, curving concrete roof that will also generate solar power.

The self-supporting, doubly curved shell roof has multiple layers: the heating and cooling coils and the insulation are installed over the inner concrete layer. A second, exterior layer of the concrete sandwich structure encloses the roof, onto which builders install thin-film photovoltaic cells.

Philippe Block, a professor of architecture and structures at ETH Zurich, and Arno Schlüter, a professor of architecture and building systems, led the team. They want to put the new lightweight construction to the test and combine it with intelligent and adaptive building systems.

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Our guest on this episode of the ECS Podcast is Shirley Meng, professor of NanoEngineering at the University of California, San Diego. Meng founded the Sustainable Power and Energy Center, the goal of which is solving key technical challenges in distributed energy generation, storage, and power management.

Meng is also the principal investigator of Laboratory for Energy Storage and Conversion research group. Her group is focused on functional nano and micro-scale materials for energy storage and conversion.

She talked to Rob Gerth, ECS’s director of marketing and communications.

Listen to the podcast and download this episode and others for free on Apple Podcasts, SoundCloud, Podbean, or our RSS Feed. You can also find us on Stitcher and Acast.

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A new kind of lithium sulfur battery could be more efficient, less expensive, and safer than currently available lithium batteries.

“We demonstrated this method in a coin battery,” says Donghai Wang, associate professor of mechanical engineering at Penn State. “But, I think it could eventually become big enough for cell phones, drones, and even bigger for electric vehicles.”

Lithium sulfur batteries should be a promising candidate for the next generation of rechargeable batteries, but they are not without problems. For lithium, the efficiency in which charge transfers is low, and, lithium batteries tend to grow dendrites—thin branching crystals—when charging that do not disappear when discharged.

The researchers examined a self-formed, flexible hybrid solid-electrolyte interphase layer that is deposited by both organosulfides and organopolysulfides with inorganic lithium salts. The researchers report that the organic sulfur compounds act as plasticizers in the interphase layer and improve the mechanical flexibility and toughness of the layer. The interphase layer allows the lithium to deposit without growing dendrites. The Coulombic efficiency is about 99 percent over 400 recharging discharging cycles.

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By: Timothy J. Jorgensen, Georgetown University

Ask people to name the most famous historical woman of science and their answer will likely be: Madame Marie Curie. Push further and ask what she did, and they might say it was something related to radioactivity. (She actually discovered the radioisotopes radium and polonium.) Some might also know that she was the first woman to win a Nobel Prize. (She actually won two.)

But few will know she was also a major hero of World War I. In fact, a visitor to her Paris laboratory in October of 1917 – 100 years ago this month – would not have found either her or her radium on the premises. Her radium was in hiding and she was at war.

For Curie, the war started in early 1914, as German troops headed toward her hometown of Paris. She knew her scientific research needed to be put on hold. So she gathered her entire stock of radium, put it in a lead-lined container, transported it by train to Bordeaux – 375 miles away from Paris – and left it in a safety deposit box at a local bank. She then returned to Paris, confident that she would reclaim her radium after France had won the war.

With the subject of her life’s work hidden far away, she now needed something else to do. Rather than flee the turmoil, she decided to join in the fight. But just how could a middle-aged woman do that? She decided to redirect her scientific skills toward the war effort; not to make weapons, but to save lives.

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A new sodium-based battery can store the same amount of energy as a state-of-the-art lithium ion at a substantially lower cost.

As a warming world moves from fossil fuels toward renewable solar and wind energy, industrial forecasts predict an insatiable need for battery farms to store power and provide electricity.

Chemical engineer Zhenan Bao and materials scientists Yi Cui and William Chueh of Stanford University aren’t the first researchers to design a sodium ion battery. But they believe their approach has the price and performance characteristics to create a sodium ion battery that costs less than 80 percent of a lithium ion battery with the same storage capacity.

$150 a ton

“Nothing may ever surpass lithium in performance,” Bao says. “But lithium is so rare and costly that we need to develop high-performance but low-cost batteries based on abundant elements like sodium.”

With materials constituting about one-quarter of a battery’s price, the cost of lithium—about $15,000 a ton to mine and refine—looms large. Researchers say that’s why they are basing the new battery on widely available sodium-based electrode material that costs just $150 a ton.

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A new flexible, paper-based supercapacitor could power wearable electronics.

The device uses metallic nanoparticles to coat cellulose fibers in the paper, creating supercapacitor electrodes with high energy and power densities—and the best performance so far in a textile-based supercapacitor.

By implanting conductive and charge storage materials in the paper, the researchers’ layer-by-layer technique creates large surface areas that function as current collectors and nanoparticle reservoirs for the electrodes. Testing shows that devices fabricated with the technique can be folded thousands of times without affecting conductivity.

“This type of flexible energy storage device could provide unique opportunities for connectivity among wearable and internet of things devices,” says Seung Woo Lee, an assistant professor in the Woodruff School of Mechanical Engineering at the Georgia Institute of Technology. “We could support an evolution of the most advanced portable electronics. We also have an opportunity to combine this supercapacitor with energy-harvesting devices that could power biomedical sensors, consumer and military electronics, and similar applications.”

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A closer look at catalysts is giving researchers a better sense of how these atom-thick materials produce hydrogen.

Their findings could accelerate the development of 2D materials for energy applications, such as fuel cells.

The researchers’ technique allows them to probe through tiny “windows” created by an electron beam and measure the catalytic activity of molybdenum disulfide, a two-dimensional material that shows promise for applications that use electrocatalysis to extract hydrogen from water.

Initial tests on two variations of the material proved that most production is coming from the thin sheets’ edges.

Researchers already knew the edges of 2D materials are where the catalytic action is, so any information that helps maximize it is valuable, says Jun Lou, a professor of materials science and nanoengineering at Rice University whose lab developed the technique with colleagues at Los Alamos National Laboratory.

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Tech Highlights was prepared by David Enos and Mike Kelly of Sandia National Laboratories, Colm Glynn and David McNulty of University College Cork, Ireland, Zenghe Liu of Verily Life Science, and Donald Pile of Rolled-Ribbon Battery Company. This article was originally published in the fall 2017 issue of Interface. Read the full article.

The Effect of the Fluoroethylene Carbonate Additive in Full Lithium-Ion Cells

In recent years, high voltage cathode materials have attracted a great deal of attention due to the high energy densities that they offer. However, side reactions with conventional electrolytes resulting in electrolyte decomposition need to be overcome to make the use of these materials viable for commercial cells. Consequently, various electrolyte additives have been the subject of much research. A team led by researchers from Uppsala University has investigated the effect of fluoroethylene carbonate (FEC) as an electrolyte additive in full Li-ion cells consisting of a LiNi_0.5Mn_1.5O₄ cathode and a Li₄Ti₅O₁₂ anode. Read the full paper.

From: B. Aktekin, R. Younesi, W. Zipprich et al., J. Electrochem. Soc., 164, A942 (2017).

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Engineers working to make solar cells more cost effective ended up finding a method for making sonar-like collision avoidance systems in self-driving cars.

The twin discoveries started, the researchers say, when they began looking for a solution to a well-known problem in the world of solar cells.

Solar cells capture photons from sunlight in order to convert them into electricity. The thicker the layer of silicon in the cell, the more light it can absorb, and the more electricity it can ultimately produce. But the sheer expense of silicon has become a barrier to solar cost-effectiveness.

So the engineers figured out how to create a very thin layer of silicon that could absorb as many photons as a much thicker layer of the costly material. Specifically, rather than laying the silicon flat, they nanotextured the surface of the silicon in a way that created more opportunities for light particles to be absorbed.

Their technique increased photon absorption rates for the nanotextured solar cells compared to traditional thin silicon cells, making more cost-effective use of the material.

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The development of prosthetics has changed many lives, providing mobility options and allowing for more active lives. But all artificial limbs aren’t perfect. Some can be painful, difficult to use, and lead to possible skin infections. The Office of Naval Research is looking to change that, providing new options for those in need of artificial limbs.

By teaming up with the Walter Reed National Military Medical Center, the Office of Naval Research has developed a “smart” artificial leg, using sensor technology to monitor walking, alter the way the user wears the prosthetic to aid in comfortability and reduce wear and tear, and warn of potential infection risks. They’re referring to this development as Monitoring Ossolntegrated Prosthesis (MOIP).

“This new class of intelligent prostheses could potentially have a profound impact on warfighters with limb loss,” says Liming Salvino, a program officer in ONR’s Warfighter Performance Department. “MOIP not only can improve quality of life, but also usher in the next generation of prosthetic limbs.”

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