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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Just a few months ago, business magnate Elon Musk announced that he would spearhead an effort to build the world’s largest lithium-ion battery in an effort to deliver a grid-scale battery to expand South Australia’s renewable energy supply. Now, reports state that Musk is delivering on his promise, stating that the battery is already half complete.

The battery is set to sustain 100 megawatts of power and store that energy for 129 megawatt hours. That roughly translates to enough energy to power 30,000 homes. On top of this large technological order, Musk stated that if his team could not develop the battery in 100 days or less, it would be free for the Australian transmission company.

“This serves as a great example to the rest of the world of what can be done,” Musk told an audience in Australia, as reported by ABC news. “To have that [construction] done in two months; you can’t remodel your kitchen in that period of time.”

The battery is expected to cost $39 million (USD). The operational deadline, as decided by the Australian government, is December 1, 2017.

Submit your manuscripts to the Journal of The Electrochemical Society (JES) Focus Issue on Processes at the Semiconductor-Solution Interface by October 22, 2017.

This issue of JES will address the most recent developments in processes at the semiconductor-solution interface including etching, oxidation, passivation, film growth, electrochemical and photoelectrochemical processes, water splitting, electrochemical surface science, electroluminescence, photoluminescence, surface texturing, and compound semiconductor electrodeposition, for photovoltaics, energy conversion and related topics.

It will include both invited and contributed papers on both fundamental and applied topics of both bulk and nanoscale materials. The following areas are of particular interest:

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By: Melanie Ohi, University of Michigan and Michael Cianfrocco, University of Michigan

Cryo-electron microscopy resolution continues to improve. Veronica Falconieri, Sriram Subramaniam, National Cancer Institute, National Institutes of Health, CC BY-NC

Many people will never have heard of cryo-electron microscopy before the announcement that Jacques Dubochet, Joachim Frank and Richard Henderson had won the 2017 Nobel Prize in chemistry for their work developing this technology. So what is it, and why is it worthy of this honor?

Cryo-electron microscopy – or cryo-EM – is an imaging technology that allows scientists to obtain pictures of the biological “machines” that work inside our cells. Most amazingly, it can reconstruct individual snapshots into movie-like scenes that show how protein components of these biological machines move and interact with each other.

It’s like the difference between having a list of all of the individual parts of an engine versus being able to see the engine fully assembled and running. The parts list can tell you a lot, but there’s no replacement for seeing what you’re studying in action.

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Stephen Maldonado is an associate professor at the University of Michigan, where he leads a research group that focuses on the study of heterogeneous charge transfer processes relevant to the fields of electronics, chemical sensing, and energy conversion/storage technologies. He was recently reappointed as an associate editor for the Journal of The Electrochemical Society (JES) in the area of physical and analytical electrochemistry, electrocatalysis, and photoelectrochemistry.

ECS: When did you become an ECS associate editor? What made you pursue an editorial role at ECS?

Stephen Maldonado: I started my time as an ECS associate editor in 2014. I pursued the opportunity for two different reasons. The minor reason was that I was genuinely curious about the “sausage making” process of accepting/rejecting a paper. That is, as an author, I had prepared and submitted plenty of papers but I had little idea about the other side of it. I had reviewed plenty of papers, too, but how those reviews factored into the final fate of the submission was a mystery.

The major reason, though, is that electrochemistry has been a principal aspect of my adult life. I got into science because, at a fundamental level, I thought electrochemistry was cool. Accordingly, my interests were aligned with the ECS at the start and it has been a major influence on my professional development. After getting tenure, I felt the time was right to give back to this community. So when I was asked to consider the position, I jumped at the chance.

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Lithium batteries made with asphalt could charge 10 to 20 times faster than the commercial lithium-ion batteries currently available.

The researchers developed anodes comprising porous carbon made from asphalt that show exceptional stability after more than 500 charge-discharge cycles.

A high-current density of 20 milliamps per square centimeter demonstrates the material’s promise for use in rapid charge and discharge devices that require high-power density.

“The capacity of these batteries is enormous, but what is equally remarkable is that we can bring them from zero charge to full charge in five minutes, rather than the typical two hours or more needed with other batteries,” says James Tour, the chair in chemistry and a professor of computer science and of materials science and nanoengineering at Rice University.

The Tour lab previously used a derivative of asphalt—specifically, untreated gilsonite, the same type used for the battery—to capture greenhouse gases from natural gas. This time, the researchers mixed asphalt with conductive graphene nanoribbons and coated the composite with lithium metal through electrochemical deposition.

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