Archive for critical materials
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What an active field!
(PNAS) Certain bacterial enzymes, the diiron hydrogenases, have turnover numbers for hydrogen production from water as large as 104/s. Their much smaller common active site, composed of earth-abundant materials, has a structure that is an attractive starting point for the design of a practical catalyst for electrocatalytic or solar photocatalytic hydrogen production from water. In earlier work, our group has reported the computational design of [FeFe]P/FeS2, a hydrogenase-inspired catalyst/electrode complex, which is efficient and stable throughout the production cycle. However, the diiron hydrogenases are highly sensitive to ambient oxygen by a mechanism not yet understood in detail. An issue critical for practical use of [FeFe]P/FeS2 is whether this catalyst/electrode complex is tolerant to the ambient oxygen. We report demonstration by ab initio simulations that the complex is indeed tolerant to dissolved oxygen over timescales long enough for practical application, reducing it efficiently. This promising hydrogen-producing catalyst, composed of earth-abundant materials and with a diffusion-limited rate in acidified water, is efficient as well as oxygen tolerant.
(ProEdgeWire/WSJ) After every election, there’s a mad scramble in Washington over the must-make-it-happen agenda for the newly inaugurated president and Congress. There are welcome signs from the White House’s own Material Genome Initiative that securing America’s access to critical metals and minerals will be high on the list. A good thing, too. Jobs and capital increasingly flow to countries that command the resources to power modern manufacturing, and American manufacturing is more dependent on metals and minerals access than ever before. Yet there is no country on the planet where it takes longer to get a permit for domestic mining. Among other consequences of this red tape, there are now 19 strategic metals and minerals for which the U.S. is currently 100 percent import-dependent-and for 11 of them a single country, China, is among the top three providers.
Researchers at the Universities of Toronto and St. Francis Xavier, Canada, are developing an affordable, energy efficient and ultrasensitive nanosensor that has the potential to detect even one molecule of carbon dioxide. Current sensors used to detect CO2 at surface sites are either very expensive or they use a lot of energy. And they’re not as accurate as they could be. Improving the accuracy of measuring and monitoring stored CO2 is seen as key to winning public acceptance of carbon capture and storage as a greenhouse gas mitigation method. With funding from Carbon Management Canada, Harry Ruda of the Centre for Nanotechnology at UT and David Risk of StFX are working on single-nanowire transistors that should have unprecedented sensitivity for detecting CO2 emissions. CMC, a national network that supports game-changing research to reduce CO2 emissions in the fossil energy industry as well as from other large stationary emitters, is providing Ruda and his team $350,000 over three years. The grant is part of CMC’s third round of funding which saw the network award $3.75 million to Canadian researchers working on eight different projects. Risk is also using a CMC grant to work on marrying specialized sensor-housings, called forced diffusion chambers, with fiber-optic CO2 sensors.
It would be a terrible thing if laboratories striving to grow graphene from carbon atoms kept winding up with big pesky diamonds. “That would be trouble, cleaning out the diamonds so you could do some real work,” says Rice University theoretical physicist Boris Yakobson, chuckling at the absurd image. Yet something like that keeps happening to experimentalists working to grow two-dimensional boron. Boron atoms have a strong preference to clump into 3D shapes rather than assemble into pristine single-atom sheets, like carbon does when it becomes graphene. And boron clumps aren’t nearly as sparkly. Yakobson and his Rice colleagues have made progress toward 2D boron through theoretical work that suggests the most practical ways to make the material and put it to work. Earlier calculations by the group indicated 2D born would conduct electricity better than graphene. Through first-principle calculations of the interaction of boron atoms with various substrates, the team came up with several possible paths experimentalists may take toward 2D boron. Yakobson feels the work may point the way toward other useful 2D materials.
(Nature) Diamond-based quantum devices can now make nuclear magnetic resonance measurements on the molecular scale. Work by two independent groups will make it easier to find out the structure of single biological molecules such as proteins without destroying or freezing them. Nuclear magnetic resonance (NMR) and its close cousin magnetic resonance imaging (MRI) give information about a sample’s structure by detecting the weak magnetic forces in certain atomic nuclei, such as hydrogen. They work by detecting how molecules collectively resonate—like guitar strings that vibrate together—with electromagnetic waves of specific wavelengths. The techniques provide information about the structure of samples without damaging them, which is particularly important if the sample is a human body. But to some researchers, whole bodies are less interesting than the molecules that they are made up of. “I want to push NMR and MRI to the molecular level,” says Friedemann Reinhard, a physicist at the University of Stuttgart in Germany. His team is one of two that have used NMR to detect hydrogen atoms in samples measuring just a few nanometres across. The second team was led by Daniel Rugar, manager of nanoscale studies at IBM’s Almaden Research Center in San Jose, Calif. Both studies are published in Science.
(GigaOm) But the next generation of lithium ion batteries are promising to be safer, and a few of them are already starting to be used in real-world situations in the power grid, electric vehicles and gadgets… So what makes Seeo’s batteries safer? It largely involves improvements to the electrolyte, or the medium that shuttles lithium ions back and forth between the cathode and the anode to charge and discharge the battery. Traditional lithium-ion battery electrolytes are mostly made of liquids, while Seeo is using a solid dry polymer based electrolyte, which feels like plastic to the touch. The polymer is non-flammable and when combined with using lithium foil as the anode, the battery can be ultra light weight and also have a high energy density, or amount of energy that can be stored per a given weight. If traditional lithium ion batteries are overcharged they can have a margin of error in the danger zone of about 20 percent above the max voltage of the battery, explained Zarem. In contrast, Seeo batteries have a margin of error of 100 percent over the voltage. The batteries also won’t burst into flames if something penetrates it (for example, during a car crash).
The Advanced Manufacturing Office of DOE’s Office of Energy Efficiency and Renewable Energy will be holding a half-day workshop on April 3 in Arlington, Va., to “discuss foundational aspects for a Critical Materials Energy Innovation Hub.” The registration deadline is soon — March 30!
The workshop anticipates a Funding Opportunity Announcement and will explain the concept of critical materials, review background and introduce the Critical Materials Hub focus and expectations.
The Hub’s mission includes “identifying more efficient use of critical materials in energy technologies and improving the efficiency, and reducing the production costs, for supplies of critical materials” to help reduce the risk of supply shortages and interruptions for domestic manufacturers.
Outside of the DOE realm, see “Issues of scarce materials in the United States,” by Steve Freiman and Lynnette Madsen in the the April issue of The Bulletin (see e-magazine version online) for an in-depth analysis of critical and scarce materials. Freiman also was a guest on a recent Kojo Nnamdi radio show on the subject.
There have been long-standing and well-known strains between China and much of the rest of the world over rare earth supplies, but projections for 2012 look like access to the materials won’t be an immediate concern because demand is less than expected. It is hoped that this provides valuable breathing space for other nations and regions to flesh-out their strategic plans (rather than being lulled into believing a crisis has passed) related to critical materials.
Bloomberg News Service earlier this week ran a story about this (with a misleading headline, “China may double rare earth exports as demand rebounds”) about how the external market demand for China’s exports ran below the quotas set for 2011. To be clear, what Bloomberg means is not that China is doubling its export limits. On the contrary, the export quotas for 2012 apparently will be about the same as for 2011, but demand is expected to more closely match the quota maximum.
To put an even finer point on this, according to a recent document on the website of China’s Ministry of Commerce, “China’s rare earth exports totaled 14,750 tons in the first 11 months of 2011, accounting for 49 percent of total export quotas. Large quantity of most export quotas still lay idle. Even though, confronted with huge pressure of resource, environment and domestic demand, in order to guarantee international market demand and keep rare earth supplies basically stable, export quota of 2012 are equal to that of 2011.” In other words, the open demand for Chinese rare earth products shifted in 2011 from being greater than quota amounts to less than half of the quota.
What caused the shift? Of course, the economic problems of North America, Europe, Japan and many other regions were a huge factor. Bloomberg reports that another factor is that the growing prices for some rare earths made consuming businesses decide to tap and deplete their existing inventories before placing new orders.
At least two other factors are also at work. One is that buyers apparently are still finding ways to purchase rare earths through less-than-legal Chinese channels. Second, the higher prices provide an incentive for non-Chinese producers to dig and refine their reserves, so other minor supply streams are at work.
Meanwhile, trade dispute and diplomatic efforts are still being used to reach longer-term solutions. For example, the topic of rare earth supplies came up in a meeting in early February between Chinese Premier Wen Jiabao and German Chancellor Angela Merkel. Wen reportedly told Merkel, “Although we now know that we must develop rare earth metals sustainably, we can still afford to meet 90 percent of global demand with less than 50 percent of the world’s reserves.”
The 189-page report evaluates the issues relevant to critical materials for wind turbines, photovoltaic thin films, electric vehicles and energy efficient lighting in terms of criticality, market dynamics and technology. The report looks at the rare earth elements that are most used in energy technology and also other elements, such as lithium (see graphic).
Here are the highlights adapted from the executive summary.
Sixteen elements were assessed for criticality in wind turbines, EVs, PV cells and fluorescent lighting. The methodology used was adapted from one developed by the National Academy of Sciences. The criticality assessment was framed in two dimensions: importance to clean energy and supply risk. Five rare earth elements — dysprosium, terbium, europium, neodymium and yttrium — were found to be critical in the short term (present-2015). These five REEs are used in magnets for wind turbines and electric vehicles or phosphors in energy-efficient lighting. Other elements-cerium, indium, lanthanum and tellurium — were found to be near-critical. Between the short term and the medium term (2015-2025), the importance to clean energy and supply risk shift for some materials.
In the past year, the prices of many of the elements assessed in this report have been highly volatile, in some cases increasing tenfold. This Strategy includes a chapter exploring market dynamics related to rare earth metals and other materials [including growing demand and slow response from global suppliers, university activities, business reactions to price volatility and material scarcity and roles for government.
Building on the 2010 Critical Materials Strategy, this report features three in-depth technology analyses.
Rare earth elements play an important role in petroleum refining, but the sector’s vulnerability to rare earth supply disruptions is limited. Lanthanum is used in fluid catalytic cracking, an important part of petroleum refining. However, lanthanum supplies are less critical than some other rare earths and refineries have some ability to adjust input amounts. Recent lanthanum price increases have likely added less than a penny to the price of gasoline.
Manufacturers of wind power and electric vehicle technologies are pursuing strategies to respond to possible rare-earth shortages. Permanent magnets containing neodymium and dysprosium are used in wind turbine generators and electric vehicle motors. Manufacturers of both technologies are currently making decisions on future system design, trading off the performance benefits of neodymium and dysprosium against vulnerability to potential supply shortages. For example, wind turbine manufacturers are deciding among gear-driven, hybrid and direct-drive systems, with varying levels of rare earth content. Some EV manufacturers are pursuing rare-earth-free induction motors or switched reluctance motors as alternatives to PM motors.
As lighting energy efficiency standards are implemented globally, heavy rare earths used in lighting phosphors may be in short supply. In the US, two sets of lighting energy efficiency standards that come into effect in 2012 will likely increase demand for fluorescent lamps containing phosphors made with europium, terbium and yttrium. The first set of standards applies to general service bulbs. The second set of standards applies to linear fluorescent lamps. The projected increase in US demand for CFLs and efficient LFLs corresponds to a projected increase in global CFL demand, suggesting upward price pressures for rare earth phosphors in the 2012-2014 timeframe, when europium, terbium and yttrium will be in short supply. In the future, light-emitting diodes (which are highly efficient and have much lower rare earth content) are expected to play a growing role in the market, reducing the pressure on rare earth supplies.
The executive summary also outlines DOE’s strategy, which is three-fold: diversify global supply chains (systemic risk management), develop substitute materials and improve recycling/reuse. The strategy was developed through a series of DOE workshops held between Nov. 2010 and Oct. 2011.
The six appendices provide much of the specifics, such as detailed evaluations for each element, market share data for each energy technology, congressional legislation, joint governmental international conference information, DOE funding activities and REE use in refineries.
The report appears to be well organized and comprehensive. The addition of subheadings to the table of contents would have been helpful for navigating quickly through the document.