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Low-temperature SOFCs: (A) Functionally graded bismuth oxide (Electrolyte 1) / ceria (Electrolyte 2) can allow use of hydrocarbon fuels at the anode at reduced temperatures. (B) Estimation of power output with LT-SOFCs from a single cell to a module (upper) and schematic diagram of power requirements according to various applications (lower). Credit: E.D. Wachsman, K.T. Lee; Science.

We’ve all heard stories of college kids who drop out even though they are falling short of graduation by one or two classes. That’s what two of my best friends did despite good grades. With those two, boredom, vision (or lack thereof) and money were factors. One became a truck driver, and the other … well, he went on to invent Tofurky(!). However, aside from sheer audacity, it didn’t make any sense to me then that they would walk away from such an investment (even at 1970s tuition costs).

That’s the same point Eric Wachsman et al. made about the United State’s policy and apparently diminishing support for solid oxide fuel cell R&D in his recent paper in Energy & Environmental Science. Their EES piece mainly is a policy plea emphasizing the foolishness (my word, not theirs) iof Congress and the Administration if they withdraw support for SOFCs by yanking the funding plug for the Solid State Energy Conversion Alliance in the FY 2012 and 2013 budgets.

Their argument boils down to this:

• The US has an international strategic advantage of hydrocarbon-based fuels (coal, natural gas, etc.), which will continue to be used in the foreseeable future, plus an infrastructure for distributing those fuels.
• Fuel cells are the most efficient means to directly convert these fuels to usable electrical energy.
• US fuel cell research has made considerable progress in the past, and is on the cusp of a new generation of breakthroughs that make portable power, transportation and stationary (utility and combined heat and power) applications much closer.

The last point above has been made, however, for many years if not decades, and begs for elaboration if it is to be taken seriously.

And, take it seriously they do! In the latest issue of Science, he and Kang Taek Lee, both affiliated with the University of Maryland’s Clark School of Engineering, report on significant advancements in SOFC technology, particularly in regard to high power densities— approximately 2 watts per square centimeter—with low temperature SOFCs (≤650°C). This, according to University of Maryland news release, is the highest mark set to date in that temperature range. Wachsman and Lee even report on significant advancements for SOFCs operating ≤350°C.

Other groups have demonstrated energy densities of ~2 W/cm², but at higher temperatures (800°C) and only in button-sized units of yttria-stabilized zirconia, and these approaches have been plagued with interconnect and other problems as upscaling attempts have been made.

Wachsman and Lee have taken a different materials path, initally using a functionally graded ceria/bismuth oxide bilayered electrolyte “where the [gadolinium cerium oxide] layer on the anode (fuel) side protects the [erbia-stablized bismuth oxide] layer from decomposing while the ESB layer on the cathode (oxidant) side blocks the leakage current through the GDC layer because of its high transference number (ratio of ionic to total conductivity).”

They then worked to optimize the thickness and composition of the bilayered GDC/ESB arrangement. The 650°C power density breakthrough happened when they fabricated “an anode-supported cell composed of a thin, dense GDC(~10 μm)/ESB(~4 μm) bilayered electrolyte with a newly developed high-performance bismuth ruthenate-bismuth oxide (BRO7-ESB) composite cathode.”

Is 2 W/cm² significant? They note that the renowned Bloom Energy stationary SOFC units operate with only one-tenth this density. Moreover, Bloom’s units operate at approximately 900°C, a characteristic that brings a raft of other problems.

But, in a more practical sense, 2 W/cm^{2 b} brings a wide range of real-world applications much closer than previously expected. 2 W/cm² puts LT-SOFC’s power density, pound for pound, ahead of internal combustion engines; if specific energy is used as a yardstick, the LT-SOFC and IC are equivalent.

^“Thus,” the authors say, “because our LT-SOFC has essentially the same power and energy density as an IC engine, it could potentially transform the automotive sector as, for example, a range extender for plug-in hybrid electric vehicles operating on conventional fuels. The corresponding 10-kW stack would only be a small cube of 10 cm per edge.” As the illustration above indicates, the cells packaged in various stack and module combinations deliver a hefty power output range of 200 W to 100 kW.

These achievements alone argue for continued federal SOFC support, but Wachsman and Lee are frustrated because, they say, there is a huge amount of layer and electrode microstructure optimization ahead (including work that is currently underway and planned) that is starting to demonstrate feasible performance levels at the 350°C level, including the use of materials that have high tolerance for carbon coking and other problems that enter the picture at lower temperatures.

And, if operating temperatures drop to 350°C… then the ball really starts rolling with faster start-ups (think cars and trucks), and better-performing and less expensive interconnects and sealants that can be mass produced.

Going back to the issue of federal policy related to SOFC development, Wachsman suggests in the news release that a major problem is that fuel cells and hydrogen have been linked too closely. “There is a problem in the perception of the public and policy makers, and in the funding of our fuel cell programs, that hydrogen and fuel cells are linked. Hydrogen-based fuel cells are the technology that has gotten all of the press and as a result we’re still waiting for a future hydrogen infrastructure. Yes, fuel cells can run off hydrogen, but they don’t have to.”

But that misperception, he continues, “has turned fuel cells into a ‘future technology’ and has resulted in a drastic reduction in the funding of fuel cell research by the DOE in favor of developing electric cars, when in fact fuel cells can be used right now in many stationary and mobile applications, including centralized power distribution and power generation for homes, businesses, and industry.”

He and Lee concede in Science that SOFC technology “has not fully matured.” But, given recent progress and plans for advancing the R&D work, and given the US strategic resources, LT-SOFCs have bright future for highly efficient applications that range from portable power sources to industrial-scale units. They conclude by saying, “LT-SOFC should be a technology of choice for these applications as long as we are in a hydrocarbon-based energy infrastructure.

Wachsman’s and Lee’s paper in Science is “Lowering the Temperature of Solid Oxide Fuel Cells” (doi:10.1126/science.1204090).

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NexTech’s 10 µm MCO coating on SS441 substrate 900°C, 200 hours, air. Credit: NexTech.

Here’s what we are hearing:

PPG to increase global production capacity for precipitated silica

PPG Industries announced that it is increasing its global precipitated silica production capacity by more than 18,000 tons per year in response to growing global demand. The capacity expansion includes projects at PPG’s Lake Charles, La., and Delfzijl, Netherlands, manufacturing locations. PPG pioneered the development of synthetic precipitated silica, becoming one of the first manufacturers to bring them to market in the 1930s. Today, PPG’s silica products business is a global leader in the manufacture of precipitated silica for tire, battery separator, carrier, coatings, industrial rubber, footwear and silicone end-use applications. The business also makes TESLIN substrate, a microporous sheet material used for card, specialty print, in-mold graphic, tag and label use, as well as technology-focused applications such as e-Passports and RFID cards and labels.

Altair board appoints H. Frank Gibbard president and CEO; Stephen B. Huang to be vice president and CFO

Gibbard has more than 30 years of experience in battery and fuel cell businesses, having served as vice president for research, Development and advanced engineering at Duracell and as CEO of the fuel cell company H Power Corp. At H Power he led a $104 million IPO that resulted in a NASDAQ listing in 2000. He holds a Ph.D. in physical chemistry from the MIT and is a frequent speaker at technical and business conferences on electrochemical energy storage. Huang is a seasoned financial executive with 18 years of experience with U.S. companies, ranging from controller to CFO. He is fluent in Mandarin Chinese and experienced in the financial management of joint US-Chinese companies. His experience in setting up and managing operations in China is particularly valuable for Altair’s expansion in global markets.

Mettler Toledo issues new white paper on transfer of weighing data for process control

Mettler Toledo is pleased to issue a new white paper that provides points to consider when defining operating boundaries, and data objectives for transfer of weighing process data to PLC, MES or ERP systems. Efficient transfer of weighing process data to higher level PLC, MES or ERP systems makes manufacturing processes more efficient and more transparent. It can result in more accurate or faster filling and control processes. Increased transparency can improve asset use, reduce operating costs, and make complying with certification standards or industrial regulations easier. But identifying and implementing the most effective system for data transfer and integration can be challenging.

NexTech Materials demonstrates stainless steel protective coatings for 40,000+ hours of operation in SOFCs

A critical challenge in the commercialization of solid oxide fuel cells is the selection and manufacture of components that will last for thousands of hours, but at an economical cost. NexTech Materials Ltd. has performed accelerated stability tests that predict a service life of over 40,000 hours at 750°C for low cost ferritic steel (AL 441 HP) interconnect components protected by its manganese-cobalt spinel. coatings. This achievement represents a critical milestone for intermediate temperature solid oxide fuel cells. To date, SOFC system lifetime has been limited by the metal component oxidation. As demonstrated by NexTech, MCO protective coatings reduce the oxidation rate of ferritic steels by a factor of twenty or more.

Momentive To Expand Specialty Quartz Plant in Geesthacht, Germany

Momentive Performance Materials Inc.’s Quartz & Ceramics is expanding its specialty quartz production facility in Geesthacht, Germany. The $14 million expansion project t will enable Momentive to meet increasing global demand for its high-purity specialty fused quartz crucibles, used by the photovoltaic industry to produce solar wafers and the semiconductor industry in the production of computer chips. The company manufactures a variety of specialty products that are essential to the photovoltaic wafer and semiconductor microchip production, including fused quartz crucibles used to “grow” silicon ingots, large-diameter fused quartz tubing, rods, and solid ingot in which silicon wafers are processed to make microchips.

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Investigators at Harvard’s School of Engineering and Applied Sciences have created strange optical effects, including corkscrew-like vortex beams, by reflecting light off a flat, nanostructured surface. Credit: Nanfang Yu, SEAS.

Check ‘em out:

How Apple could revolutionize solar

Flight time of Stalker small UAS quadrupled to 8 hours with ruggedized propane SOFC

From a flat mirror, ‘designer light:’ An optical phenomenon that defies laws of reflection and refraction

3D lithography by rapid curing of the liquid instabilities at nanoscale

Students: Apply for the Bernard S. Baker Student Award for fuel cell research or new Sir Alistair Pilkington Award for glass research

Rolla researchers predict they can cut cooling costs by 40 percent

Nanopillars on surface of thin-film silicon could lead to better solar cells

Optoelectronics appear as hopeful application for graphene

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Electrochemical strain microscopy images ion mobility. The overlay shows electrochemical activity of platinum nanoparticles on a yttria-stabilized zirconia surface, showing ionic activity along the triple phase boundaries. Credit: ORNL

My favorite part of the TV hospital drama, House, is the beginning when the failure occurs. The show opens with the patient-of-the-week doing normal stuff and the camera cuts to the deconstruction going on unbeknownst inside the unlucky patient’s body. The camera zooms around, darting through veins, leaping across synapses, undulating in the ebb and flow within until—zonk!—something goes terribly wrong. The crackerjack team of doctors sure could use a probe like the one the show’s producers have—one that shows from within how things flow, interact and fail. Instead they have the brilliant but irascible Dr. House.

There are times when materials scientists, too, would benefit from getting an inside view. It can be especially helpful to be able to characterize a material dynamically and capture the material’s response as it is happening. For example, the key reaction in a solid oxide fuel cell is the oxygen reduction reaction that occurs at the triple phase boundary. The triple phase boundary (pdf) is where the solid electrolyte, catalyst and gas are in contact. It’s where the action is in a fuel cell with the oxygen reduction reaction at the cathode and the hydrogen oxidation reaction at the anode, converting chemical energy into electricity.

The TPB is a very difficult region to characterize. If the electrochemical reactions could be observed or imaged, it should be possible to understand the fundamental mechanisms controlling the material’s performance and to design improved materials.

“If we can find a way to understand the operation of the fuel cell on the basic elementary level and determine what will make it work in the most optimum fashion, it would create an entirely new window of opportunity for the development of better materials and devices,” says Amit Kumar in an ORNL press release.

Kumar is lead author of a new paper out of Oak Ridge National Laboratory that describes a new technique—electrochemical strain microscopy—that allows scientists to directly measure oxygen reduction/evolution reactions and oxygen vacancy diffusion on ion conducting solid surfaces, like yttria-stabilized zirconia.

ESM measures electrochemical reactivity and ionic current in solids on a scale of ten nanometers or less. By applying a periodic bias to a scanning probe microscopy tip in contact with the surface, ionic movement is induced, the surface deforms and the deformations are mapped. As explained in an article (pdf) by Asylum Research, a partner with ORNL on developing the technique, “The intrinsic link between concentration of ionic species and/or oxidation states of the host cation and molar volume of the material results in electrochemical strain and surface displacement.”

Regarding the importance of the capability afforded by ESM, coauthor and ACerS member Sergei Kalinin says, “When you want to understand how a fuel cell works, you are not interested in where single atoms are, you’re interested in how they move in nanometer scale volumes. The mobile ions in these solids behave almost like a liquid. They don’t stay in place. The faster these mobile ions move, the better the material is for a fuel cell application. Electrochemical strain microscopy is able to image this ion mobility.”

The technique can be used to characterize ionic conductivity for other applications as well, such as lithium batteries, metal-air batteries and semiconductors.

Kalinin, co-theme leader for Functional Imaging on the Nanoscale at ORNL, says in an email to us, “The ORR/OER directly underpin the operation of fuel cells and metal–air batteries, and hence their probing on the level of a single electrocatalytic nanoparticle or structural defect is of direct interest for energy storage and conversion. Furthermore, these processes can severely affect (through oxygen nonstoichiometry) the functionality of the materials of interest for condensed matter physics community. After all, materials used in fuel cells—manganites, cobaltites, etc.—are the same as those studied for colossal magnetoresistance or nanoscale phase separation.”

The paper is “Measuring oxygen reduction/evolution reactions on the nanoscale,” A. Kumar, et. al., Nature Chemistry 3, 707-713 (2011) doi:10.1038/nchem.1112
Published online 14 August 2011

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Fuel cell powered bus in London. Credit: Tom Page, Creative Commons.

Fuel cell supporters have generally been disappointed that the DOE hasn’t done more for the technology or hydrogen-based technologies, but the agency hasn’t totally lost interest. A few days ago, DOE announced grants of nearly $7 million (over five years) for four cost analyses related to fuel cells and hydrogen storage systems.

In a news release, DOE describes the deliverables as “rigorous cost estimates for manufacturing equipment, labor, energy, raw materials, and various components that will help identify ways to drive down production costs of transportation fuel cell systems, stationary fuel cell systems, and hydrogen storage systems.”

“These projects will help advance our fuel cell and hydrogen storage research efforts and bring down the costs of producing and manufacturing next generation fuel cells,” says Secretary Steven Chu in the release.

Here are the four projects:

Directed Technologies Inc. ($3 million for two projects): One project will focus on the cost of light-duty vehicles and bus transportation fuel cell systems. The other project will focus on cost analyses of hydrogen storage systems with particular emphasis on capital equipment, raw materials, labor and energy “to gain an understanding of system cost drivers and future pathways to lower system costs.” Wisely, the company has been asked to build sensitivity analysis into its models to determine which variables (fuel cell system design, platinum price, power density, operating pressure and temperature, number of cells in stack, etc.) affect manufacturing costs the most.

Lawrence Berkeley National Lab ($1.9 million): The lab will focus on costs related to low- and high-temperature stationary fuel cell systems up to 250 kilowatts. This project will look at several variables, including manufacturing techniques, production volume and system designs.

Battelle Memorial Institute ($2 million): Battelle will have two areas of focus. The first is on stationary fuel cell applications up to 25 kW, e.g., forklifts, backup power and primary power units. It will also examine combined heat and power systems. The other will look at 100 to 250 kW systems, again including backup power, primary power and CHP systems.

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