Colorado School of Mines researchers report to have succeeded in developing affordable and efficient ceramic fuel cells that could be used to power homes from five years worth of work. The research would enable more efficient use of natural gas for power generation through the use of fuel cells that convert the chemical energy of a fuel source into electrical energy close to where it is used.
The research, led by Mines Professor Ryan O’Hayre, would enable more efficient use of natural gas for power generation through the use of fuel cells that convert the chemical energy of a fuel source into electrical energy.
Natural gas, the reliable environmentally friendly fuel source alternative would help guarantee greater energy security while distributed generation technologies would lead to reduced energy costs for consumers.
O’Hayre said, “Our work demonstrates a proton-conducting ceramic fuel cell that generates electricity off of either hydrogen or methane fuel and runs at much lower temperatures that conventional ceramic fuel cells. We achieved this advance by developing a new air electrode for our fuel cell that is highly active even at lower temperatures because it is a triple-conducting electrode (it conducts electron holes, oxygen ions, and protons all at the same time) and we applied a relatively new fabrication method that greatly reduces the complexity and cost for the fuel cell fabrication.”
Its great news, but the article is behind a $20 paywall. Shame, it was funded by ARPA-E under the REBELS program, The National Science Foundation using tax dollars and the Petroleum Institute who would likely be thrilled to get some public notice. Its the eternal twisting of money now over the long term public interest, pay for the work and then pay to see the results. Then again there wouldn’t be any peer review journals without some cash flow.
July 29, 2015 | Leave a Comment
University of Wisconsin-Madison (UWM) chemists have introduced a new fuel cell catalyst approach that uses a molecular catalyst system instead of solid catalysts. The team is on a quest for better, less expensive ways to store and use energy where platinum and other precious metals play an important role.
Platinum and other precious metals serve as catalysts to propel the most efficient fuel cells, but they are costly and rare. The UWM team looks to have a metal-free alternative catalyst for fuel cells that may be at hand.
In a study published July 15 in ACS Central Science, the team of introduced a new approach that uses a molecular catalyst system instead of precious metals. Although molecular catalysts have been explored before, earlier examples were much less efficient than the traditional platinum catalyst.
The research may be important because a fuel cell converts chemical energy into electricity by reacting hydrogen and oxygen at two different electrodes and catalysts make the reactions more efficient.
UWM chemistry Professor Shannon Stahl and lab scientist James Gerken took inspiration from their group’s previous work with catalysts that use oxygen in applications for the chemical industry. They noticed a striking similarity between these aerobic oxidation reactions and the oxygen reaction in fuel cells and decided to see if they could apply a similar approach to a fuel cell.
The new catalyst is composed of a mixture of molecules called nitroxyls and nitrogen oxides. These molecular partners play well together; one reacts well with the electrode while the other reacts efficiently with the oxygen.
Professor Stahl said, “While this catalyst combination has been used previously in aerobic oxidations, we didn’t know if it would be a good fuel cell catalyst. It turns out that it is the most effective molecular catalyst system ever reported.”
Because the approach involves chemical reactions between gases, liquids and solids, moving from concept to demonstration was no small feat. Gerken spent months studying and optimizing each component of the setup they had envisioned before testing everything in a model system.
“This work shows for the first time that molecular catalysts can approach the efficiency of platinum,” Gerken said. “And the advantage of molecules is that you can continue to modify their structure to climb further up the mountain to achieve even better efficiency.”
This is one more breakout into the catalyst field that eventually will get to practical commercial fuel cells. Its interesting to see the team made the connection from industrial applications. The astonishing thing is the how effective the catalysts perform. For the catalyst community this is quite significant and for future consumers cause for more confidence on the new products to come.
A team of chemists at the University of California, Riverside have succeeded in “upconverting” photons in the visible and near-infrared regions of the solar spectrum. The innovation is an ingenious way to make solar energy conversion more efficient.
When installing solar cells, the labor cost and the cost of the land to array them are the bulk of the expense. Solar cells often made of silicon or cadmium telluride rarely cost more than 20 percent of the total cost. If each solar cell could be coaxed to generate more power solar energy could be made cheaper as less land (or less roof) would need to be purchased.
Christopher Bardeen, a professor of chemistry in a collaborative effort between him and Ming Lee Tang, an assistant professor of chemistry explained, “The infrared region of the solar spectrum passes right through the photovoltaic materials that make up today’s solar cells. This is energy lost, no matter how good your solar cell. The hybrid material we have come up with first captures two infrared photons that would normally pass right through a solar cell without being converted to electricity, then adds their energies together to make one higher energy photon. This upconverted photon is readily absorbed by photovoltaic cells, generating electricity from light that normally would be wasted.”
Bardeen added that these materials are essentially “reshaping the solar spectrum” so that it better matches the photovoltaic materials used today in solar cells. The ability to utilize the infrared portion of the solar spectrum could boost solar photovoltaic efficiencies by 30 percent or more.
In their experiments, Bardeen and Tang worked with cadmium selenide and lead selenide semiconductor nanocrystals. The organic compounds they used to prepare the hybrids were diphenylanthracene and rubrene. The cadmium selenide nanocrystals could convert visible wavelengths to ultraviolet photons, while the lead selenide nanocrystals could convert near-infrared photons to visible photons.
In lab experiments, the researchers directed 980-nanometer infrared light at the hybrid material, which then generated upconverted orange/yellow fluorescent 550-nanometer light, almost doubling the energy of the incoming photons. The researchers were able to boost the upconversion process by up to three orders of magnitude by coating the cadmium selenide nanocrystals with organic ligands, providing a route to higher efficiencies.
“This 550-nanometer light can be absorbed by any solar cell material,” Bardeen said. “The key to this research is the hybrid composite material combining inorganic semiconductor nanoparticles with organic compounds. Organic compounds cannot absorb in the infrared but are good at combining two lower energy photons to a higher energy photon. By using a hybrid material, the inorganic component absorbs two photons and passes their energy on to the organic component for combination. The organic compounds then produce one high-energy photon. Put simply, the inorganics in the composite material take light in; the organics get light out.”
The ability to upconvert two low energy photons into one high energy photon has potential applications beyond solar energy – in biological imaging, data storage and organic light-emitting diodes. Bardeen emphasized that the research could have wide-ranging implications.
“The ability to move light energy from one wavelength to another, more useful region, for example, from red to blue, can impact any technology that involves photons as inputs or outputs,” he said.
We’re going to have to watch this team. This ingenuity has great prospects for a major improvements in solar cell development and progress. Aside from the practical, its an astounding innovation!
National Institute of Standards and Technology (NIST) scientists have put firm numbers on the high costs of installing pipelines to transport hydrogen fuel and also found a way to reduce those costs. The scientists calculated that hydrogen-specific steel pipelines can cost as much as 68% more than natural gas pipelines.
But the research is showing hydrogen transport costs could be reduced safely for most pipeline sizes and pressures by modifying industry codes to allow the use of a higher-strength grade of steel alloy without requiring thicker pipe walls.
Pipelines like so many other activities are subjected to regulation and codification. That’s a good thing in many respects. Many of us are familiar with ISO (International Standards Organization) programs and standards. Along with UL Listing, ISO offers consumers some confidence that the product or service meets a good level of competency for the investment. For those on the lookout their money is far better spent.
The other side is the uncountable number bureaucrats, politicians and lobbyists busily trying to wield power over everything and everyone they can survey. While the activity does tend to weed out the worst players, the expense and never ending dabbling adds huge costs to the economy. Ultimately there are the lawyers at the end – er, before a reset.
Hopefully the NIST has a head start, on a matter what will likely involve federal agencies, states, counties and even municipalities. The human aggression to wield power over others knows no limit. Now is the time for the hydrogen community to get with it as these kinds of issues can slow things up by decades.
Pipelines to carry hydrogen cost more than other gas pipelines because of the measures required to combat the damage hydrogen does to steel’s mechanical properties over time.
The NIST researchers calculated that hydrogen-specific steel pipelines can cost as much as 68% more than natural gas pipelines, depending on pipe diameter and operating pressure. By contrast, a widely used cost model suggests a cost penalty of only about 10%. The team’s study paper has been published in Science Direct.
The good news, according to the NIST work, is that hydrogen transport costs could be reduced for most pipeline sizes and pressures by modifying industry codes to allow the use of a higher-strength grade of steel alloy without requiring thicker pipe walls. The stronger steel is more expensive, but dropping the requirement for thicker walls would reduce materials use and related welding and labor costs, resulting in a net cost reduction. The code modifications, which NIST has proposed to the American Society of Mechanical Engineers (ASME), would not lower pipeline performance or safety, the NIST authors say.
NIST materials scientist James Fekete, a co-author of the study explained, “The cost savings comes from using less – because of thinner walls – of the more expensive material. The current code does not allow you to reduce thickness when using higher-strength material, so costs would increase. With the proposed code, in most cases, you can get a net savings with a thinner pipe wall, because the net reduction in material exceeds the higher cost per unit weight.”
The NIST study is part of a federal effort to reduce the overall costs of hydrogen fuel, which is renewable, nontoxic and produces no harmful emissions. Much of the cost is for distribution, which likely would be most economical by pipeline. The U.S. contains more than 300,000 miles of pipelines for natural gas but very little customized for hydrogen. Existing codes for hydrogen pipelines are based on decades-old data. NIST researchers are studying hydrogen’s effects on steel to find ways to reduce pipeline costs without compromising safety or performance.
As an example, the new code proposal would allow a 24-inch pipe made of high-strength X70 steel to be manufactured with a thickness of 0.375 inches for transporting hydrogen gas at 1500 pounds per square inch (psi). (In line with industry practice, ASME pipeline standards are expressed in customary units.)
According to the new NIST study, this would reduce costs by 31% compared to the baseline X52 steel with a thickness of 0.562 inches, as required by the current code.
In addition, thanks to its higher strength, X70 would make it possible to safely transport hydrogen through bigger pipelines at higher pressure (36-inch diameter pipe to transport hydrogen at 1500 psi) than is allowed with X52, enabling transport and storage of greater fuel volumes. This diameter-pressure combination is not possible under the current code.
The proposed code modifications were developed through research into the fatigue properties of high-strength steel at NIST’s Hydrogen Pipeline Material Testing Facility. In actual use, pipelines are subjected to cycles of pressurization at stresses far below the failure point, but high enough to result in fatigue damage.
Unfortunately, it is difficult and expensive to determine steel fatigue properties in pressurized hydrogen. As a result, industry has historically used tension testing data as the basis for pipeline design, and higher-strength steels lose ductility in such tests in pressurized hydrogen. But this type of testing, which involves steadily increasing stress to the failure point, does not predict fatigue performance in hydrogen pipeline materials, Fekete says.
NIST research has shown that under realistic conditions, steel alloys with higher strengths (such as X70) do not have higher fatigue crack growth rates than lower grades (X52). The data have been used to develop a model for hydrogen effects on pipeline steel fatigue crack growth, which can predict pipeline lifetime based on operating conditions.
This work is just getting going and more study needs done to pile up the competency of the data so that the ASME can adopt a standard that would not set off an avalanche of federal state and local regulation and interference. Even more important is the certain assurance to land owners and those living in close proximity to the future’s hydrogen pipelines that the standard is better than just good enough.
University of Toronto engineers have combined two promising solar cell materials together for the first time, creating a new platform for LED technology. The team has designed a way to embed the strongly luminescent nanoparticles called colloidal quantum dots into perovskite.
Researchers in The Edward S. Rogers Sr. Department of Electrical & Computer Engineering invented something totally new combining two promising solar cell materials together for the first time, creating a new platform for LED technology.
Perovskites are a family of materials that can be easily manufactured from solution, and that allow electrons to move swiftly through them with minimal loss or capture by defects.
Xiwen Gong, one of the study’s lead authors and a PhD candidate working with Professor Ted Sargent said, “It’s a pretty novel idea to blend together these two optoelectronic materials, both of which are gaining a lot of traction. We wanted to take advantage of the benefits of both by combining them seamlessly in a solid-state matrix.”
The resulting material is a black crystal that relies on the perovskite matrix to ‘funnel’ electrons into the quantum dots, which are extremely efficient at converting electricity to light. Hyper-efficient LED technologies could enable applications from the visible-light LED bulbs in every home, to new displays, to gesture recognition using near-infrared wavelengths.
Dr. Riccardo Comin, a post-doctoral fellow in the Sargent Group said, “When you try to jam two different crystals together, they often form separate phases without blending smoothly into each other. We had to design a new strategy to convince these two components to forget about their differences and to rather intermix into forming a unique crystalline entity.”
The main challenge was making the orientation of the two crystal structures line up, called heteroexpitaxy. To achieve heteroepitaxy, Gong, Comin and their team engineered a way to connect the atomic ‘ends’ of the two crystalline structures so that they aligned smoothly, without defects forming at the seams. “We started by building a nano-scale scaffolding ‘shell’ around the quantum dots in solution, then grew the perovskite crystal around that shell so the two faces aligned,” explained coauthor Dr. Zhijun Ning, who contributed to the work while a post-doctoral fellow at UofT and is now a faculty member at ShanghaiTech.
The resulting heterogeneous material is the basis for a new family of highly energy-efficient near-infrared LEDs. Infrared LEDs can be harnessed for improved night-vision technology, to better biomedical imaging, to high-speed telecommunications.
Combining the two materials in this way also solves the problem of self-absorption, which occurs when a substance partly re-absorbs the same spectrum of energy that it emits, with a net efficiency loss. “These dots in perovskite don’t suffer reabsorption, because the emission of the dots doesn’t overlap with the absorption spectrum of the perovskite,” explained Comin.
Gong, Comin and the team deliberately designed their material to be compatible with solution-processing, so it could be readily integrated with the most inexpensive and commercially practical ways of manufacturing solar film and devices. Their next step is to build and test the hardware to capitalize on the concept they have proven with this work.
“We’re going to build the LED device and try to beat the record power efficiency reported in the literature,” says Gong.
Go guys. Better, cheaper, faster, brighter and more efficient – sign me up.