Engineers have, for the first time, come up with a way to safely charge a smartphone wirelessly using a laser.

A narrow, invisible beam from a laser emitter can deliver charge to a smartphone sitting across a room—and potentially charge the phone’s battery as quickly as a standard USB cable.

To accomplish this, the researchers mounted a thin power cell to the back of a smartphone, which charges the smartphone using power from the laser.

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Flexible materialStress a muscle and it gets stronger. Mechanically stress a new rubbery material—say with a twist or a bend—and it automatically stiffens by up to 300 percent, the engineers say.

In lab tests, mechanical stresses transformed a flexible strip of the material into a hard composite that can support 50 times its own weight.

This new composite material doesn’t need outside energy sources such as heat, light, or electricity to change its properties. And it could be used in a variety of ways, including applications in medicine and industry.

The researchers found a simple, low-cost way to produce particles of undercooled metal—that’s metal that remains liquid even below its melting temperature. Researchers created the tiny particles (they’re just 1 to 20 millionths of a meter across) by exposing droplets of melted metal to oxygen, creating an oxidation layer that coats the droplets and stops the liquid metal from turning solid. They also found ways to mix the liquid-metal particles with a rubbery elastomer material without breaking the particles.

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SolarResearchers have developed a new titanium-based material that is a good candidate for making lead-free, inorganic perovskite solar cells.

In a new paper, which appears in the journal Joule, the researchers show that the material is especially good for making tandem solar cells—arrangements in which a perovskite cells are placed on top of silicon or another established material to boost the overall efficiency.

Perovskites have emerged as a promising alternative to silicon for making inexpensive and efficient solar cells. But for all their promise, perovskites are not without their downsides. Most contain lead, which is highly toxic, and include organic materials that are not particularly stable when exposed to the environment.

“Titanium is an abundant, robust, and biocompatible element that, until now, has been largely overlooked in perovskite research,” says senior author Nitin Padture, professor of engineering and director of the Institute for Molecular and Nanoscale Innovation.

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Perspective on Fuel Cells

Fuel Cell CarFuel cells play a major role in creating a clean energy future, with a broad set of applications ranging from powering buildings to electrifying transportation. But, as with all emerging technologies, researchers have faced many barriers in developing affordable, efficient fuel cells and creating a way to cleanly produce the hydrogen that powers them.

In a new Perspective article, published in the Journal of The Electrochemical Society, researchers are aiming to tackle a fundamental debate in key reactions behind fuel cells and hydrogen production, which, if solved, could significantly bolster clean energy technologies.

In the open access article, “Perspective—Towards Establishing Apparent Hydrogen Binding Energy as the Descriptor for Hydrogen Oxidation/Evolution Reactions,” Yushan Yan and his coauthors from the University of Delaware provide an authoritative overview of work done in the areas of hydrogen oxidation and evolution, present key questions for debate, and provide paths for future innovation in the field.

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SemiconductorA small metallic tab that, when attached to the body, is capable of generating electricity from bending a finger and other simple movements could one day power our electronic devices.

“No one likes being tethered to a power outlet or lugging around a portable charger. The human body is an abundant source of energy. We thought: ‘Why not harness it to produce our own power?’” says Qiaoqiang Gan, associate professor of electrical engineering in the School of Engineering and Applied Sciences at the University at Buffalo and lead author of a paper describing the tab in the journal Nano Energy.

The tab is a triboelectric nanogenerator. Triboelectric charging occurs when certain materials become electrically charged after coming into contact with a different material. Most everyday static electricity is triboelectric.

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SolarResearchers have proposed three different methods for providing consistent power in 139 countries using 100 percent renewable energy.

The inconsistencies of power produced by wind, water, and sunlight and the continuously fluctuating demand for energy often hinder renewable energy solutions. In a new paper, which appears in Renewable Energy, the researchers outline several solutions to making clean power reliable enough for all energy sectors—transportation; heating and cooling; industry; and agriculture, forestry, and fishing—in 20 world regions after all sectors have converted to 100 percent clean, renewable energy.

The researchers previously developed roadmaps for transitioning 139 countries to 100 percent clean, renewable energy by 2050 with 80 percent of that transition completed by 2030. The present study examines ways to keep the grid stable with these roadmaps.

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By: Naga Srujana Goteti, Rochester Institute of Technology; Eric Hittinger, Rochester Institute of Technology, and Eric Williams, Rochester Institute of Technology

Renewable grideCarbon-free energy: Is the answer blowing in the wind? Perhaps, but the wind doesn’t always blow, nor does the sun always shine. The energy generated by wind and solar power is intermittent, meaning that the generated electricity goes up and down according to the weather.

But the output from the electricity grid must be controllable to match the second-by-second changing demand from consumers. So the intermittency of wind and solar power is an operational challenge for the electricity system.

Energy storage is a widely acknowledged solution to the problem of intermittent renewables. The idea is that storage charges up when the wind is blowing, or the sun is shining, then discharges later when the energy is needed. Storage for the grid can be a chemical battery like those we use in electronic devices, but it can also take the form of pumping water up a hill to a reservoir and generating electricity when letting it flow back down, or storing and discharging compressed air in an underground cavern.

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By: Joshua M. Pearce, Michigan Technological University

SolarFalling costs for solar power have led to an explosive growth in residential, commercial and utility-scale solar use over the past decade. The levelized cost of solar electricity using imported solar panels – that is, the solar electricity cost measured over the life of the panels – has dropped in cost so much that it is lower than electricity from competing sources like coal in most of America.

However, the Trump administration on Jan. 22 announced a 30 percent tariff on solar panel imports into the U.S. This decision is expected to slow both the deployment of large-scale solar farms in the United States and the rate of American solar job growth (which is 12 times faster than the rest of the economy). The tariff increases the cost of solar panels by about 10 to 15 cents per watt. That could reduce utility-scale solar installations, which have come in under $1 per watt, by about 11 percent.

The tariffs may lead China and other countries to appeal the move with the World Trade Organization. But could innovations in solar power compensate for tariffs on panels?

In my research, I have found that one solar technology – previously largely ignored because of low-cost photovoltaics, or PV, panels – could make a comeback: the humble mirror, or booster reflector, as it is known in the technical literature.

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By: Joshua D. Rhodes, University of Texas at Austin

Solar panelsEditor’s note: On Jan. 22, 2018, the Trump administration announced plans to impose punitive duties on solar panels imported from abroad. This decision came in response to a complaint filed by two solar companies, but much of the industry opposes the action, which trade groups say will increase the cost of solar projects and depress demand. To illustrate what’s at stake, energy scholar Joshua Rhodes provides some context on the U.S. solar industry and its opportunities and challenges.

How big is the U.S. solar industry, and what is its growth trajectory?

The U.S. solar industry generated US$154 billion in economic activity in 2016, including direct sales, wages, salaries, benefits, taxes and fees. Its revenues have grown from $42 million in 2007 to $210 million in 2017.

About 25 percent of total new power plant capacity installed in 2017 came from solar. Total installed U.S. solar capacity is over 50 gigawatts – the equivalent generating capacity of 50 commercial nuclear reactors.

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A new water-based air-conditioning system cools air to as low as 18 degrees Celsius (about 64 degrees Fahrenheit) without using energy-intensive compressors and environmentally harmful chemical refrigerants.

This technology could potentially replace the century-old air-cooling principle that is still used in modern-day air-conditioners. Suitable for both indoor and outdoor use, the new system is portable and can be customized for all types of weather conditions.

The team’s novel air-conditioning system is cost-effective to produce, and it is also more eco-friendly and sustainable.

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