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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Li-ion fuel cell

Superior high-voltage performance of Li-ion full cell with Li-rich layered oxide cathode prepared with fluorinated polyimide (FPI) binder, compared to the cell with conventional binder PVdF. (Click to enlarge.)
Image: Seung Wan Song

In order to increase the driving range of electric vehicles, researchers across the globe are working to develop lithium-ion batteries with higher energy storage. Now, scientists at Chungnam National University and Kumoh National Institute of Technology in Korea are taking a step toward that goal with their development of the first high-voltage cathode binder for higher energy Li-ion batteries.

Today’s Li-ion batteries are limited to charge to 4.2V due to the electrochemical instability of the liquid electrolyte and cathode-electrolyte interface, and loosening of conventional binder, polyvinylidenefluoride (PVdF), particularly at elevated temperatures. The fabrication of Li-rich layered oxide cathode with a novel high-voltage binder, as the research team demonstrated, can overcome these limitations.

Charging the batteries with Li-rich layered oxide cathode (xLi2MnO3∙(1−x)LiMO2, M = Mn, Ni, Co) to higher than 4.5V produces approximately doubled capacity than those with LiCoO2 cathode, so that doubled energy density batteries can be achieved.

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Fuel CellApplying a tiny coating of costly platinum just 1 nanometer thick—about 1/100,000th the width of a human hair—to a core of much cheaper cobalt could bring down the cost of fuel cells.

This microscopic marriage could become a crucial catalyst in new fuel cells that use generate electricity from hydrogen fuel to power cars and other machines. The new fuel cell design would require far less platinum, a very rare metal that sold for almost $900 an ounce the day this article was produced.

“This technique could accelerate our launch out of the fossil-fuel era,” says Chao Wang, an assistant professor of chemical and biomolecular engineering at Johns Hopkins University and senior author of a study published in the journal Nano Letters.

“It will not only reduce the cost of fuel cells,” Wang says. “It will also improve the energy efficiency and power performance of clean electric vehicles powered by hydrogen.”

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