Below is the text version for the "HyMARC: Addressing Key Challenges to Hydrogen Storage in Advanced Materials Through a Multi-Lab Collaboration" webinar held on January 9, 2019.
Eric Parker, Fuel Cell Technologies Office
Good day everyone and welcome to the U.S. Department of Energy’s Fuel Cell Technologies Office webinar for January 2019. We’ve got a great presentation this month from Sandia National Laboratories and the National Renewable Energy Laboratory on HyMARC or addressing key challenges to hydrogen storage and advanced materials through a multi-lab collaboration. My name is Eric Parker. I provide program support within the Fuel Cell Technologies Office and I’m the organizer for today’s meeting.
We’ll begin in just a second, but first I have a few housekeeping items to tell you about. As you may have heard, today’s webinar is being recorded. And the recording along with the full slide deck you’ll see today will be posted online so stay tuned. Also if you have any questions throughout the webinar that you think of, please be sure to type in your question in the chat box you should see in WebEx and send it to host and we’ll be sure to address those during the Q&A portion at the end of the presentation today. And with that, I would like to introduce today’s DOE webinar host, Ned Stetson, who is joining us at DOE HQ. Hi Ned.
Ned Stetson, Fuel Cell Technologies Office
Thank you Eric. Good afternoon and good morning to everyone and happy new year to you all. I hope everyone’s 2019 has gotten off to a good start. I’m the program manager for the hydrogen storage activities here at the DOE Hydrogen Fuel Cell Technologies Office and I want to welcome you to our second webinar describing some of the hydrogen storage activities we’re supporting here in the DOE’s Fuel Cell Technologies Office. On December 6, we held a webinar to discuss the new activities on hydrogen carrier materials for improved hydrogen storage transport. That presentation slides and recording of the presentation can be accessed through the DOE’s Fuel Technologies Office website.
Today’s webinar will describe the Hydrogen Materials Advanced Research Consortium (or HyMARC for short) which we established several years ago. Today’s webinar will be presented by the HyMARC co-directors Dr. Tom Gennett and Mark Allendorf of Sandia National Labs. So a little background. In 2015 hydrogen storage program established two national lab teams: the HyMARC core team and a second team which was dubbed HySCORE. The work was formally launched at the beginning of fiscal year 2016.
So while the two teams have collaborated and worked closely together from the very start, we initially kept a firewall between them since HySCORE team was also charged with carrying out performance validation activities for our program. However, over the past three years it’s become obvious that there could be many more benefits if we fully integrated the two teams and had them work together seamlessly rather than maintaining a firewall. And therefore as we develop the phase two program which you’ll be hearing about today, we fully merged the two teams under the HyMARC umbrella.
So what is HyMARC? Well, Tom and Mark will give you the details of the consortium and the work activities they have planned. I want to provide you some background and the purpose and objective of this effort. HyMARC is a consortium member of the DOE’s Energy Materials Network. The Energy Materials Network is a set of national-lab consortia established to facilitate access to the DOE’s national work capabilities and resources to help accelerate develop materials to solve challenges in various energy applications. More information about the Energy Materials Network and the current consortium members can be found at the DOE’s Office of Energy Efficiency and Renewable Energy website.
So as hydrogen fuel cell vehicles and other hydrogen-related applications become commercialized, the storage of hydrogen has clearly been identified as one of the leading challenges. This is driven in part by reactivity and combustion properties of hydrogen, but is especially being driven by the low energy density of hydrogen. By mass, hydrogen has the highest specific energy but by volume has the lowest energy density. Therefore to store sufficient quantities to meet driving needs for a car for instance, the hydrogen has to be stored in either very high pressures—current fuel cell vehicles use some of our 10,000 psi pressure vessels—or at very low temperatures.
The normal boiling point of hydrogen is 20 kelvin, which is minus 253 degrees Celsius or minus 423 degrees Fahrenheit depending on your unit of preference. But even if they use high pressures and low temperatures, the energy density of hydrogen is significantly less than conventional liquid fuels such as gasoline and diesel. But this means that storage containing units are therefore very large and tend to be heavy and expensive to be able to contain either the high pressure or the low temperatures which prevents boil off losses. So an improved storage technology is highly desirable.
Another option for storing hydrogen is using materials. Atomic hydrogen can be bound to materials through chemical bonds, this is metal hydrides, or molecular hydrogen can be physisorbed on the surface of porous materials such as activated carbons or metal organic frameworks. The actual density of hydrogen in many of these materials can be significantly higher than either compressed or liquified hydrogen. For instance aluminum hydride, also known as alane or magnesium iron hydride, these two materials based on the crystal structure has a hydrogen density at ambient temperature and pressure that is more than twice that of liquid hydrogen.
So for years the holy grail has been—for hydrogen storage has been to develop materials that had this right set of kinetic and thermodynamic properties, along with all of the physical properties such as the hydrogen by mass, hydrogen by volume, et cetera to allow for low pressure, high density hydrogen storage in ambient conditions. However after years of research, materials have been identified with many of these properties but not a single material has been identified that has all of the appropriate properties to be viably used in many of these applications such as on board fuel cell vehicles.
We therefore established HyMARC to address this challenge. The national lab core team is charged with carrying out foundational research to help further understand the interaction of hydrogen and materials and develop computational synthetic and characterization tools to accelerate hydrogen storage material development. The national lab core team is also charged with working with individual projects that have been selected through either funding opportunity announcements, lab calls, or other mechanisms such as cooperative research and development agreements (or CRADAs) to accelerate the research progress.
For HyMARC we’ve had two rounds of four topics to which we’ve selected nine seedling projects to work with HyMARC on the proposed high-risk, high-reward materials concept. Projects selected to move forward, collaborate with a lab team having access to the expertise of researchers as well as the computations and data characterization resources within the consortium. Of the nine selected so far eight have gone through the phase one go/no go decision points. Four have met the criteria and moved to phase two. Other proposed programs, four have not met their criteria and the projects have been ended.
I want to emphasize we are looking for very challenging material development goals and through the four topics are looking for highly innovative, although scientifically feasible, high-risk, high-reward research proposals. We therefore expect a high percentage will not progress past the first phase of the program. So that’s just a little bit of background on HyMARC.
I’ll now turn it over to the HyMARC co-directors to tell you more about the consortium itself and their research plans. Dr. Mark Allendorf is a senior scientist at Sandia National Laboratories. He’s a chemist with degrees from Washington University of St. Louis and Stanford University. He is a present emeritus fellow at the Electrochemical Society and received the 2014 R&D 100 award for novel approach to radiation detection.
Dr. Tom Gennett follows joint appointments as a principal scientist at the National Renewable Energy Lab as well as being a professor and a department head of chemistry at the department, at the chemistry department at the School of Mines in Colorado. He is also a chemist with degrees from State University of New York in Potsdam and also from my alma mater, University of Vermont. Prior to joining NREL, he was professor for 18 years at the Rochester Institute of Technology and he currently holds the title of emeritus there. So with that, I’ll turn it over to I believe to you Mark, right?
Dr. Mark D. Allendorf, Sandia National Laboratories
Hello everyone. This is Mark Allendorf. It’s my pleasure to give this overview of HyMARC. Before I do that, I want to thank Ned first for that introduction but also with his colleagues Jesse Adams and Zeric Hulvey for their very strong support of this effort and of course for the funding from EERE’s Fuel Cell Technologies Office. Next slide please. This is a brief outline of the material I intend to cover. Ned has already given the fuel cells technology intro and covered some of the overview of HyMARC but I’ll reiterate a little bit of that in terms of the goals and tell you a little bit about the Phase One accomplishments.
We’re referring to Phase One accomplishments. We’re referring to Phase One as the previous three years, so that’s fiscal year ’16 through ’18. We’re now in Phase Two which is projected to last for another four years starting this fiscal year. So I’ll tell you a little bit about our research tasks and some of the projects that are involved. And then I’ll get into HyMARC capabilities which is an important deliverable of the HyMARC effort. And finally I’ll give you a few brief examples of some ongoing research and try to wrap that up with 15 minutes or so left for question and answers.
Next slide please. So as shown here in this hexagon at the top, HyMARC is comprised of six national laboratories. As Ned said, the core team originally in the first phase was Sandia, Lawrence Livermore, and Lawrence Berkeley but that has now been merged with three other, well, with Pacific Northwest Lab, NREL, and a second effort at Lawrence Berkeley. We are also closely aligned with the neutron facilities at NIST. There are two HyMARC-funded post docs there and also with user capabilities at SLAC. So this is the research team that comprises HyMARC.
You see below there the icons from various seedling projects. And the arrow going both ways is intended to indicate that HyMARC and these projects collaborate very closely with each other. I’ll tell you a little bit more about the roles of HyMARC in assisting these projects and trying to help them meet their go, don’t go milestones. But in general, the objectives of HyMARC are to first develop and enhance what we call core capabilities for hydrogen storage research. This is, in particular, computational models and databases, new characterization tools and methods that can probe basically all relevant length scales of hydrogen storage materials, and then tailorable synthetic platforms that are designed to be reproducible and also allow us to probe specific aspects of phenomena such as nanoscale confinement and processes on surfaces.
But a second important aspect of HyMARC is to validate results that are produced either by the seedling projects or other work throughout the world on hydrogen storage and also to validate our own theories and models for hydrogen storage. This is quite crucial to the strategic plan of FCTO, which wants to invest its funding as effectively as possible. We of course also want to accelerate the path forward to developing hydrogen storage materials and the rest of the presentation hopefully give you a sense of how we go about doing that.
Next slide please. So this is just a little introduction to some of the individuals that are involved. The pictures and names here are of the PIs at the different laboratories and their primary investigative assistance. You can see some of these names may not be familiar to you but all have long track records in the hydrogen storage field or in specific areas of characterization such as the neutron work at NIST and X-ray work that’s being done at SLAC. Next slide please.
So as Ned mentioned, just a little bit of history: about four years or so ago FCTO convened a workshop of major players in the hydrogen storage research field and asked the question, “Why is it that we don’t have any materials at that time that can meet all of the DOE technical targets?” And there are a variety of reasons but one of the main ones is that we still lack a great deal of fundamental understanding of the processes that control the properties of these materials. And by properties we principally mean the ability to release and uptake hydrogen and do that in a way that meets these targets.
So you can see on the right there the spider chart shows these various targets. And the ones that are underlined in red are ones that HyMARC has particularly been focusing on. It’s important to remember that HyMARC is not specifically driven by targets but we are trying to solve problems that are preventing people doing material discovery from reaching those targets and that’s why we’ve taken a little bit of a step back to do more foundational research as we call it.
So the ways that we can accelerate materials discovery includes strategic assessments, which means that we look at different strategies for developing or improving materials. We try to provide thermodynamic and other data that are either missing or known to be inaccurate. And there’s some specific examples I could show you related to metal hydrides for example. Modeling tools are essential and have primarily been focused—over the past years prior to HyMARC—to thermodynamic calculations involving primarily density functional theory. We’ve gone many generations beyond that to be able to look at as I said all relevant length scales.
And then finally we assist these seedling projects and we do that in several ways. One, we provide access to experimental resources that are unique to HyMARC but vital to their success. We do provide computational modeling assistance and support some of these projects. And in some cases with data interpretation in particular cases where spectroscopic tools that we have can help identify species more definitively.
Next slide. So the two primary categories of hydrogen storage materials that concern HyMARC are metal hydrides and sorbent materials. And this little cartoon here gives you some sense of the complexity of the phenomena that are involved, in fact when HyMARC was first launched we were tasked with looking at all relevant phenomena, which covers everything from the interaction of hydrogen with the surface, to its transport into the bulk, which could be by diffusion through solid or through pores in something like a metal organic framework, to chemical reactions that lead to the nucleation and growth of new phases.
You can break this down into essentially two pieces. One is the thermodynamics and the other are the kinetics. And the EA activation energy there within that are subsumed all of these different processes that could contribute to what is the real energy required to desorb hydrogen or reabsorb it to regenerate the material. So hopefully this gives you a little bit of a sense of not only how comprehensive HyMARC’s effort is in this area but also how complex the problem is. And it really explains why until now it’s been so difficult to meet all of these technical targets. It’s a very challenging problem.
Next slide. Nevertheless and can you hit that twice please. There we go. Nevertheless we have really had some successes, some significant successes in what we say is moving the bar for specific materials and strategies. And it’s important I think to understand what the bar is now. There are of course the DOE targets. But as many of you are probably aware there are now commercially available hydrogen-powered fuel cell vehicles, and these store hydrogen by using high-pressure carbon-fiber-reinforced tanks. The pressures involved are as high as 700 bar, and this of course is expensive from both the point of view of the fueling station but also the manufacturer of the tank. And it places a lot of constraints on the design of the vehicle.
So really one of the bars is to develop materials that can beat compressed gas, not only to meet the DOE targets. And so we’ve tackled a number of different strategies and I’ll show you just a few of them are listed here. Metal hydrides in particular, their complexity has been a steep hill to climb but we’ve been looking at various strategies that can help us improve the thermodynamics and kinetics. And example of that is our efforts to probe the interfaces between hydrogenated and dehydrogenated materials. And this has resulted in some cases where we’ve had really remarkable reductions in the heat of desorption that are required. Lithium nitrite is an example where our understanding of the nanoscale effects these interfaces allowed us to reduce the [inaudible] temperature by over 180 degrees C.
In the area of sorbents, HyMARC can actually claim the development of the sorbent with the highest volumetric and gravimetric capacity at room temperature. And this is really the holy grail: to be able to store hydrogen at ambient temperature so we can eliminate the use of cryogenics, and of course to do it at lower pressures. So you’ll be able to look at these slides offline and see some of these. If you have questions about the specifics, we have published a number of articles but Tom and I would be more than happy to answer questions about those.
So let’s go to the next slide, as I mentioned publications are a very important product of HyMARC and to date we’ve had over 50 publications. I’m highlighting a couple here that I think might be particularly useful to you. One of them is a perspective article that we published in the Energy & Environmental Science journal just last year. And this is our assessment of various strategies for developing absorbent materials for vehicular storage. This is a topic that has encompassed a very large range of strategies over the years, some of which we’ve concluded are not going to be effective. But others the jury is still out. And so we attempted in this article to give our perspective on that to cite some relevant literature and give a little bit of a prognosis. And this is intended to provide information to DOE to guide future FOAs that would be designed to develop new materials.
On the right hand side there is a sort of counterpart dealing with a nanostructured metal hydride. Nanostructuring has actually in our research has been shown to be one of the most effective ways of improving the kinetics or shifting the thermodynamics of metal hydride. And we conceived a review article that we actually thought would be relatively short but were astounded to realize that there were hundreds of papers out there just within the last five years. This review I think has something like 550 references. So it’s very comprehensive. We’re optimistic actually about this strategy and I think if you take a look at this, you’ll get a sense of just how promising it can be and how exciting some of the developments are.
Next slide please. So Ned mentioned the seedling projects. The seedlings are small efforts (relatively small) that have an initial phase of 18 months to evaluate a particular well-defined strategy, and answer a specific question with a go/no go at the end of that 18 months. And if that go/no go is reached, then an additional 18 months of funding can be provided to pursue it further. So what HyMARC has done and continues to do is to assist these by, first of all, giving a designated HyMARC point of contact. And this is important because the whole team of HyMARC I think is over 40 people now. So it would be difficult to figure out just where to start if you had a specific question or need.
We of course provide technical expertise concerning specific scientific issues, and access to HyMARC capability, but I should say that this access is something that we agree on in concert with DOE, Ned in particular. And we want everyone to know that HyMARC is a standalone research organization. It’s not an analytical service. So we encourage these seedling teams to dialogue with us carefully and plan experiments which can in fact involve visitors, students, whatever actually to HyMARC laboratories. But we want to plan these very carefully so that the best use of these in many cases scarce resources can be made.
The four seedling projects listed below are the ones that Ned mentioned, now in their phase two effort. An example of what we’ve done for some of these, the one with University of Hawaii: we took samples that they sent us and exposed them to ultra-high-pressure hydrogen using a facility that we have here and then assisted them with some characterization of that. In other projects, we’ve done modeling, for example, that has assisted in the interpretation of data by the project. We also have taken prepared samples, for example, from NREL where they’ve used ALD and infiltrated them with a metal hydride to create this composite material. And with all of the projects, the ones that started and are ongoing we maintain a fairly continuous conversation with them about their progress. So this is really intended to be a collaborative effort. And we publish joint publications and have visitors to the various labs as I mentioned.
Next slide please. So HyMARC has a task structure in Phase Two, and it’s broken down as shown here first by material categories: sorbents which is led by Tom Gennett, and metal hydrides by myself. Hydrogen carriers is also a key element. That was covered in an earlier webinar, there is a link there if you’re interested. We have another task that’s focused on the development of advanced characterization capabilities led by Phil Parilla at NREL. We have an effort to specifically support the seedlings. And then finally we are bringing online a data hub, which is not open to the public at this stage but I believe it eventually will. The intention here is to collect data that can be valuable to the research community at large.
Next slide please. So within this phase two research effort that we just launched, we have a number of what we call focus areas. And these are intended to be topics with a starting point and an ending point. Some are larger efforts than others. Some are effectively exploratory kinds of efforts where we’re trying to decide whether a particular strategy is going to pay off or not. You can see a list of the overall topics here. In the area of sorbents, much of the effort is focused on either the improving the binding energy of hydrogen or the free energy (not just the entropy) to a sorbent but also trying to develop strategies for packing these in an efficient way so that there’s no loss of capacity due to macroscale pores between particles. We’re of course also looking at trying to increase the capacity and one of the principal strategies is to develop materials that can bind more than one hydrogen to an active site such as an open metal site on [inaudible].
In the area of metal hydrides it’s broken down a little bit more along the lines of a specific phenomenon. Thermodynamics of course, but also interfaces that can be either on the surface or the bulk.... Strategies for activating bonds such as boron-boron or boron-hydrogen bonds that are quite possibly rate limiting in the ability to desorb or reabsorb hydrogen.... And things like nanoscaling and microstructural effects that are both chemical and physical in nature.
But advanced characterization efforts include some very specialized facilities at NREL for doing calorimetry, NMR spectroscopy at Pacific Northwest Laboratory, which has capabilities for looking at isotopes like boron, and also solid state NMR. And also, we have access to various DOE user facilities and some other specialized methods that we’ve developed ourselves that I’ll tell you a little bit more about. So next slide.
I wanted to just give you a quick overview and a sense of the capabilities that HyMARC now has available. Modeling has been a very crucial tool. As we show here, we now have models that can address length scales that range from sub nanometer (which is of course chemical bond lengths) but also things that affect spectroscopy (like X-ray techniques), up through the molecular microscale, mesoscale, and even up to grains where we’re now talking about micron-scale materials. And then finally, bulk properties, which are essential to understanding at least in a first order sense the behavior of materials. I show a thermodynamic phase diagram there for magnesium boron hydride where we were able to combine a model with experimental data that we obtained to really upgrade and revise that understanding of the thermochemistry of that material. Next slide.
So characterization tools are also critical. Again these map to the length scales of the models. But we’re using cutting edge tools that were either not widely available when HyMARC started three years ago or not available at all. Some of the ones illustrated here are soft X-ray tools at the advanced light source, for example, which allow us to probe coordination environments among light elements. But also very sophisticated electron microscope tools, X-ray microscopy tools, shown there under the mesoscale column that allow us to look at phase evolution. And then these more macroscale tools such as high pressure reactor that provides both a way of characterizing behavior under these ultrahigh pressures, and in this case, it’s up to 1,000 bar. We can also look at the exchange of hydrogen, isotope effects, which help us look at the kinetics of the reaction of hydrogen with these materials.
Next slide. An example of where we have particularly deep capabilities is in the area of surface chemistry. Of course hydrogen has to interact with the surface of any storage material. That’s the first thing it does. But there’s sort of a misconception that some analytical tools that are widely used like X-ray tool electron spectroscopy are able to actually detect hydrogen at the surface on the mono layer surface. That is actually not correct. XPS is actually probing several nanometers into the bulk. So HyMARC actually has access to an instrument at Sandia called low energy ion scattering and this tool can actually look at the atomic mono layer and it can detect hydrogen specifically. It’s the only diagnostic tool that is capable of doing that.
So we can see hydrogen as it absorbs and dissociates on a surface and interacts with various elements that are present there. What can we learn from this? We can look at the exact surface composition, but we want to know how these surfaces respond to changes in temperature in the hydrogen environment. We’d like to look at the spatial distribution of different species and ultimately answer the question, “Can we modify or tailor these surfaces to improve hydrogen storage properties?” As you can imagine these are pretty foundational questions but they are really essential to getting a handle on how these materials behave.
Next slide please. We have some again unique capabilities within HyMARC that are experimental in nature. One of these is the DRIFTS capability: diffuse reflectance infrared Fourier transform spectroscopy. This is a tool that allows us to look at the binding of hydrogen to a material such as a sorbent and correlate that binding with different binding sites. We can also do very detailed thermo conductivity measurements. This is crucial for aspects of the heat balance when we are loading hydrogen or absorbing it from the material. And then finally variable temperature or PCT, a method for getting thermodynamic data for the uptake and release of hydrogen from various materials. The instrument that’s shown here can access hydrogen pressures up to 200 bar and temperatures up to 350 kelvin.
I want to also emphasize though that we’re not limited to looking at hydrogen. We can also look at other gases using these instruments, such as methane and CO2, and we have a suite of other characterization techniques: the sort of usual suspects such as BET and various [inaudible] based techniques that can also probe these. So we have a quite versatile toolkit here to provide insights into these materials. Next slide please.
This is also one unique both characterization and synthetic instrument that we have: the high-pressure hydrogen reaction station that is in Sandia, California. This instrument I actually was informed yesterday can actually go up to 2,000 bar and hold up to four samples and heat them up to 400 degrees C. What’s interesting about this is that it now provides us a way of looking at the behavior of materials at pressures that are now accessible in commercial fueling stations. Not that we think that necessarily that 700 bar is the optimum, but it is interesting to us to be able to push these materials as far as we could conceivably go with available commercial equipment. And in some cases, this may allow materials like certain metal hydrides to become able to meet DOE targets that could not make those targets back when the limit was something like 100 bar.
Next slide. This slide gives you a little overview (again matching the length scales) where now these are these synthetic capabilities that are designed to probe specific aspects of storage materials. And they’ve allowed us to discover some interesting unexpected phenomena. For example, using the high-pressure reactor we were able to show that there’s actually a liquid phase of magnesium boron hydride. There’s some little pictures there you can see of it. And this provided thermodynamic data that filled in some important gaps in the phase diagram.
On the other end of the spectrum though we’ve developed very well-controlled carbon materials such as these graphing nano ribbons that are shown here. These allow us to probe both the interaction of hydrogen with the surface in a way that is far more controlled than would be in a porous carbon. But also, we can functionalize the edges of these with catalytic elements, and look at the reaction of hydrogen in this very controlled environment free of a lot of complicating issues that are endemic to disordered materials, what various kinds of sorbents, not just carbon. Next slide.
I want to speed up just a little bit so I make sure we have time for some questions. I did mention that HyMARC has access to several user facilities. The emblems of these are shown here. In some cases, we have essentially dedicated access. NIST and its neutron facilities are an example of that. In others, HyMARC is essentially no different than any other user. We’ve had to write proposals to obtain access to these tools. An example is the advanced light source. We were very fortunate in the first phase of HyMARC to have what’s called an approved program at the ALS, which gives us some dedicated time over a period of three years and we’re hoping to get that renewed for another three years. It may be possible in some limited circumstances for, for example, FOA projects or new seedlings to interact with us and obtain some data from there. But by and large these are tools that are limited access that are mostly focused on these very fundamental questions that the HyMARC team is working on.
Next slide please. So let me just give you three short examples of experimental activities that we’ve been engaged in. Next slide. So sodium aluminum hydride is a sort of canonical metal hydride. It’s been studied extremely extensively and in particular its interaction of certain catalytic elements or additives such as titanium. You would think that everything is known about this material that could be known. Taking the example of the titanium additive, there is something like 2,000 papers out there that have addressed various aspects of this.
Well, we were able to apply this suite of surface and bulk characterization tools coupled very closely with computational spectroscopy, and we figured out a couple of things about this that were really not suspected. One is that titanium—whatever its role is in the desorption—it’s not occurring on the surface. We don’t see any titanium species on the surface of this material and during the process of desorption. We were able to probe that several ways, the low energy ion scattering but also ambient pressure XPS experiments at the ALS. But the other thing that we learned which really came as a surprise to us is that there are oxygenated species on the surface of this material that appear to accelerate the desorption of hydrogen. They are in fact essential to the behavior of the material and the prejudice or preconceived notion up till now has been that oxides are bad. They contaminate the surface. If they’re too thick of course they can block the access of hydrogen to the rest of the material. These experiments and calculations suggest that under controlled conditions, one may actually want a very thin oxide layer. We’re looking at that now in other hydrogen or other metal hydride materials to see just how general that phenomena is.
Next slide. I mentioned borohydrides. Borohydrides are attractive because they’re light and their gravimetric capacities can be very competitive. But they are also incredibly complex materials. Taking magnesium borohydride as our starting point, these materials have complex decompositions that produce molecular species, closo-boranes—these are kinetic intermediates. It was baffling for years trying to figure out how to stop this from happening, or what was controlling this formation. So what you see here is some modeling that we did. And this again was correlated with experiments that allowed us to look at the very early stages of the rehydrogenation of magnesium diboride.
What we learned in short is that there are different essentially defect sites in this material, basal planes where there may be magnesium or boron exposed. And the reaction of hydrogen with those sites has different activation energies. That’s what’s exhibited down here in this lower left-hand corner. Essentially what we see is that the activation energy evolves with the extent of decomposition of materials. So again this fundamental insight allows us to now conceive of strategies where we can try to force the material to go one direction rather than another and in particular the hydrogen interaction with these sites—these boron-rich edges—seem to be the ones that lead to these kinetic intermediates. So finding a way to cap those off is one strategy.
Next slide please. Finally something about sorbents that makes use of this really powerful DRIFTS capability that we have. Probing the absorption sites of hydrogen within a porous material is extremely difficult. It can be done to some extent with NMR neutron tools—they are very effective. But what we can do now with this DRIFTS is get simultaneous chemical and spatial information that can be straightforwardly compared with modeling.
So what’s shown here are some vibrational spectra taken with this DRIFTS instrument for a high capacity MOF cobalt DODBC. And this material has two different absorption sites and we can pinpoint those by using the vibrational spectrum. So you see that in the right-hand plot there: the more strongly binding material sizes is the one on the right I believe. And then the more weakly binding one which fills second is the one on the left.
So you can see in the isotherm plot that’s shown there on the left how the material fills up one site and then proceeds to the next one. So we are getting data here that we couldn’t really get any other way and is now helping us design these sorbents in a very rational way with effectively design rules for the material.
Let me just summarize very quickly, HyMARC is a national laboratory consortium with a big team of people of various interdisciplinary expertise, characterization tools, modeling synthesis are all important elements. But we also collaborate extensively both with these seedling projects and externally both nationally and internationally to offer scientific expertise, joint experiments and access to these cutting-edge capabilities. So I hope this has been informative to you but there’s some opportunity now to ask questions. Please feel free to do that and thank you very much for this opportunity to tell you about our exciting work.
Eric Parker
Thanks Mark. We’re going to open up the Q&A portion of the webinar now. Please as a reminder if you thought of any questions during the presentation please submit them now and we’ll get to as many as we can. Ned, do you want to take it from here?
Ned Stetson
Thank you Eric. So we do have a question here concerning interactions between the seedling projects and the core team. From your experiences, how have the interactions gone and how—what have been the most productive interactions between the seedling projects and the laboratory teams?
Mark Allendorf
Well, I think Tom and I can both answer that. I’ll give an answer first. Really the most productive and effective interactions have been ones where we, through careful planning, defined a very high leverage set of experiments where samples are sent to us for example and optimally where an investigator from the seedling project actually comes to the HyMARC laboratory to interact face-to-face with the research staff. Really, that’s the best way to do it. Now that isn’t always feasible. I think the key element is (1) extensive communication and (2) careful planning so that the best use of the time and the resources are made. Tom, you have anything you want to add to that?
Thomas Gennett, National Renewable Energy Laboratory
Mark said it very well. Thank you.
Ned Stetson
So we have another one here. There’s question about the purity of [inaudible] for hydrogen gas. The questioner is trying to initiate a new project to develop flexible high-temperature fuel cells that can be switched between power generation and hydrogen generation. There are many challenges. One of them is to efficiently separate hydrogen gas from CO2. So have you looked at or considered hydrogen selectivities?
Mark Allendorf
Hydrogen selectivities?
Ned Stetson
I’m assuming it’s to get their selectively separate hydrogen from other gases, in this case CO2.
Mark Allendorf
No, we have not not actually looked at that. I think the closest we’ve come to addressing the questioner’s issue is the work where we’ve looked at the oxygen on the surface. Tom, can you comment on maybe some competitive binding or other efforts that have gone on at NREL?
Thomas Gennett
Not in the HyMARC program. We don’t typically work on competitive binding with the different materials at this point in time. It’s something that we would look at in the future as you’re starting to deal with some of the high-end sorbent materials to see what you could tolerate in your hydrogen stream for some of the other gases that might be present.
Ned Stetson
One question I guess for you Tom about the validation measurements. If a project had a material that needed to be sent to NREL, how could one be sent to them? Can you give any details on how a project could have materials performance validated? And I guess there’s two types: the seedling projects or projects associated with the HyMARC and the DOE program and the projects that are not associated with HyMARC and the DOE program.
Thomas Gennett
So with the DOE-funded projects, it is usually for a go/no go decision. And those materials would be the best materials that whatever project had that would be coordinated through the DOE program manager. And then we all work together to make sure we have all the criteria. Typically, whoever the scientists are come out to make sure that all the sample preps and everything are being done correctly and then we go forward with the test that way.
It typically takes about three weeks to get a complete validation done—whether it’s 77 K or any of the other temperatures that would want to be done. When it comes to having non-DOE samples, we are contacted… we always request initial data before we would start and then depending upon what the individual would want tested, there is a certain cost structure that we have set up that we would be happy to share with them at that time.
Ned Stetson
Thank you. Another question. Can the HyMARC [inaudible] described here be applied towards electrolysis process materials in terms of cathodes and anodes? Expanding beyond hydrogen storage materials and hydrogen generation materials.
Mark Allendorf
Well, I guess in principle but that isn’t really in our mission space. But there is an EMN, ElectroCat, that I think would be more suitable for that.
Thomas Gennett
Actually there’s another EMN, HydroGEN, which is led by NREL which actually might be more suitable.
Mark Allendorf
Yeah.
Ned Stetson
Ok. There’s been a number of questions submitted concerning working with HyMARC or future funding solicitations so I’ll actually respond to those. So so far we’ve had two rounds of seedling projects selected through funding opportunity announcements. We anticipate that there will be additional topics and funding opportunity announcements in the future so all I can say there is just watch. I recommend everybody that’s interested to go to the Fuel Cell Technologies Office website and sign up for our email blast, our newsletter because we will be announcing any funding opportunity announcements coming from the office through those so that would give you a heads up. So I recommend everybody sign up for that to get the heads up for any opportunities coming out of the office.
The other way to work with HyMARC is through cooperative research and development agreements (CRADAs). Those are actually negotiated between HyMARC team and the usually a company and is the specific requirements within the CRADA itself. For all the EMNs we have been establishing standard CRADAs so it’s a streamlined process. It removes a lot of the burden and difficulty of trying to negotiate CRADAs as we have in the past because we’ve actually tried to analyze it so that there’s minimal negotiation. Just like our nondisclosure agreement, the EMNs are basically a take it or leave it. We try to streamline it so very little negotiation or changes between mediated between one seedling project and another project with the HyMARC labs.
Eric Parker
If everyone is viewing the slides, the link at the bottom of the bottom of the current slide, if you sign up for that, you’ll be updated on the topics Ned just discussed.
Ned Stetson
And then the other way to work with HyMARC is if you have for instance a specific characterization need, such as materials absorption validation. Then, NREL in particular has a mechanism set up so that individual companies or research can have samples measured. However, there is a cost associated with that.
(Next question) So is HyMARC involved in research in aluminum hydride alane and if so what were the results?
Mark Allendorf
We’re not working on alane specifically right now. There was a seedling project that had a strategy for looking at that that unfortunately didn’t make it past its first go/no go. There was some published work out there on this. It is a promising material but right now we’re not directly working on that.
Ned Stetson
All right. Thank you. Another one just lost. Well, this one I guess is for you Mark. I’m assuming this is related to the high-pressure system. And the question how do you get the 2,000 bar and how do you measure the pressure? (I think there’s a 1,000 bar is the actual limit of the system and not 2,000.)
Mark Allendorf
Well, you get to that pressure with some specialized compressors that we have. And then the pressure is measured I believe with mechanical gauges but I have to tell you I have never done it. So I’m only telling you from the bits that I know. If you, if the questioner had some specific questions about it, I’m more than happy to put you in touch with the person who really knows all the answers.
Ned Stetson
All right. And we actually only have one more question here at the moment so if you have any more questions please send them in. We have time for a couple more. But right now we have one more and it kind of relates to an early question. Question: How does small business get involved or benefit from HyMARC, is it possible? And again, and is it possible—and again I think that is primarily the two ways the small business get involved: (1) either through a funding opportunity announcement, replying to a topic and being selected for funding and support from the DOE office and working with HyMARC. And (2) the other is to set up a CRADA with HyMARC to work directly with them through a CRADA. So with that, that’s all of the questions that we’ve received so far. So if there’s no more questions then I think I’ll turn it back over to Eric for wrap up.
Eric Parker
Thanks Ned and thank you to everyone who asked a question. We did just get one last one. We have time for one more. Ned or Mark, have neutron techniques been applied to monolayer sensitivity?
Mark Allendorf
Neutron techniques? Not that I’m aware of… I see one other question that appeared concerning power to gas projects. Do you see that one?
Eric Parker
No. But go ahead and address it if you can do it in a couple minutes.
Mark Allendorf
Well, let’s see. In various power to gas projects there was interest in storage of methane hydrogen mixtures. Example 80 percent methane and 20 percent hydrogen. Does the DOE or HyMARC have any interest in this? I would say in principle, yes. And one of the things that we’re starting to work on are hydrogen carriers. We’re not specifically considering mixtures right now, but it could evolve to that. The issue being that hydrogen is such a low volumetric density that even a high-pressure tanker truck can’t move very much of it. So we’re looking for ways to chemically and reversibly bond hydrogen in a bulk material that’s cheap enough to use as a transport medium.
Eric Parker
Ned, I think we had one more come in. A last question for the day.
Ned Stetson
Can you send it to me?
Eric Parker
Yeah.
Ned Stetson
All right. Looking at materials in large-scale storage. And actually that was the subject of the prior webinar we had on December 6. As Mark and Tom mentioned we are working on hydrogen carriers now. So hydrogen carriers are not being looked at for onboard a vehicle. It’s actually being looked at for the bulk storage and transport of hydrogen. So if you’re interested in large-scale storage, I recommend that you go to the DOE website and look up the webinar from December 6 which is specifically on hydrogen carriers.
And as you saw earlier in the presentation the hydrogen carrier work is in task with HyMARC. However, it’s one of the newer tasks and one of the newer areas to get involved with. And therefore we actually have a webinar on it. But that is specifically looking at materials for bulk storage and transport. And it will be a similar program as the projects that Mark was describing earlier where we’ll run a FOA topic and select projects through seedlings that come in with a high-risk, high-reward innovative concept to work with the laboratory team. We’ll take it through the first phase if the project seems feasible enough. If the concept is feasible, then we’ll support it for additional research; if it’s not feasible then we’ll wrap it up at that point.
Eric Parker
Ok. I’m going to have to finish up there. Sorry if we didn’t get to your question. We do have to cover a few housekeeping items in the last minute we have. First of all, please as a reminder the AMR this year is taking place from April 29 to May 1 in Crystal City, Virginia. Please visit the website there and get information. And then again please sign up for our newsletter to receive updates for the fuel cells and hydrogen energy program. And with that, I’d like to thank everyone for joining. Please feel free to email us with a specific question or concern if we didn’t get to it. And as reminder again this was recorded and the webinar and slides will be available online. And I encourage everyone to sign up for the monthly newsletter to find out about future webinars. And with that, have a great rest of your week everyone and goodbye.