Department Of Energy Office Research Articles

An Operando Study of Deep-Cycling MnO2 Cathodes for Low Cost, High Energy Density Aqueous Batteries

This talk will discuss deep cycling of MnO2 as an aqueous, low-cost battery cathode material. Deep cycling is defined as reduction through nearly all of the theoretical capacity from MnIV to MnII, or 617 mAh/g-MnO2, while remaining reversible. MnO2 is one of the safest and most inexpensive battery materials ever discovered, and is well known in consumer primary batteries. In these cells MnO2 operates by proton (H+) insertion, but is not generally considered rechargeable due to a panoply of irreversible phase changes triggered during discharge.[1] Cycleability of Bi-modified δ-MnO2 was researched in the 1980s as a candidate cathode for electric vehicle batteries.[2-4] However, while this material can achieve thousands of cycles under certain conditions, performance is generally a strong function of several factors such as cycling protocol (e.g. galvanostatic vs. CV sweeps), active material mass loading, and electrode thickness. These last two, loading and thickness, can be quantified together by an areal capacity. Modeling indicates that areal capacities of >20 mAh/cm2have potential to result in high energy density aqueous, rechargeable batteries when paired with zinc anodes. These characteristics meet the requirements for a collection of emerging applications, namely grid-scale electrical storage.[5] We have recently reported that high cycleability of Bi-modified MnO2 was achieved by further doping the material with other compounds.[6] Furthermore, this cycleability extends to high areal capacity electrodes. Figure 1 shows C/3 cycling of Bi-modified MnO2 cathodes, both with and without doping. Both electrodes had areal capacities of 21 mAh/cm2, produced from a cathode mix of 45% γ-MnO2, 9% Bi2O3, and 46% CNTs. While the undoped electrode lost significant capacity by the third cycle, the doped electrode achieved steady-state cycling after an initial conversion from γ-MnO2 to δ-MnO2during cycle 1. To establish the difference in mechanism between the two electrodes, a study was undertaken to observe the material conditions within the cathodes in operando. Energy dispersive X-ray diffraction (EDXRD) data were collected at beamline 6-BM-A at the Advanced Photon Source. Figure 2 shows diffraction data within a doped Bi-modified cathode during the second cycle as a function of location within the cathode. Both δ-MnO2 and a modified bismuth material resembling the structure of Bi12MnO20 sillenite were observed.[7] The discharge products Mn(OH)2 and metallic Bi were observed in the ranges indicated. Reversible formation of spinel Mn3O4 was also observed, apparent from the (103) and (211) reflections. This finding was significant, as spinel formation is generally considered to be irreversible in alkaline batteries, and the source of non-rechargeability. This spinel was confined to the region near the separator, while Mn(OH)2and Bi were located throughout. Further experiments using localized XANES and X-ray fluorescence to track the dopant will also be discussed. These were performed at beamline 5-ID (SRX) at the National Synchrotron Light Source II. Acknowledgements This work was supported by the U.S. Department of Energy, ARPA-E under award number DE AR0000150. This research used beamline 5-ID (SRX) of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Water Management in Low Temperature Fuel Cells through in-Operando X-Ray Computed Tomography

For polymer-electrolyte fuel cells (PEFCs) and anion exchange membrane fuel cells (AEMFCs) optimal water management is essential. During start-up and at low operating temperatures, where water is present in a liquid form, it can block reactant delivery to electrocatalyst sites, resulting in significant mass-transport losses, flooding and low fuel cell power densities. Using synchrotron X-ray computed tomography (CT) we have previously shown how water transport properties depend on porous materials morphology and chemical composition, as well as cell compression.1-3 These ex- and in-situ studies isolate specific porous membrane / electrode assembly (MEA) component’s effect on water management (such as micro-porous (MPL) or gas-diffusion layer (GDL)). To understand water transport under operating conditions we use in-operandoX-ray CT studies, where water distribution is observed under various steady-state conditions. In-operando single serpentine channel (1x1 mm) fuel cell testing hardware for synchrotron X-ray CT is used with active area of 1 cm2. Steady-state water generation and removal is observed in PEFCs and AEMFCs for temperature of 30oC with chronoamperometric holds at current densities ranges of 20 – 100 mA/cm2. Furthermore, comparison of water distribution in PGM and PGM-free catalysts for both type of fuel-cells will be presented. In all of these systems water pooling is observed at the component interfaces, indicating the importance of interfaces design. Acknowledgment: The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Facility for Rare Isotope Beams Update for Nuclear Physics News

The Facility for Rare Isotope Beams (FRIB) is a major new scientific user facility under construction in the United States for nuclear science research with beams of rare isotopes [1]. FRIB is funded by the United States Department of Energy Office of Science (DOE-SC) and is located on the campus of Michigan State University (MSU), in East Lansing, Michigan, USA. FRIB will support the mission of the Office of Nuclear Physics in the DOE-SC. The total FRIB project cost is $730 million and the facility is scheduled to be completed by 2022. The project has passed the 75% complete mark and is managed toward early completion in 2021. FRIB is estimated to provide access to 80% off all isotopes of elements lighter than uranium.

Structural Characterization of a Periplasmic Lipoprotein Associated with Magnesium Homeostasis in Salmonella enterica

The divalent magnesium cation (Mg2+) is imperative to the survival of all living organisms on earth. It stabilizes different macromolecular and cellular structures, and plays a vital role in a vast number of essential biochemical reactions. Due to its significance, many organisms have evolved complex biochemical systems to adapt to varying environmental levels of Mg2+. Additionally, the ability to adapt to environments with limiting Mg2+ is required by many bacteria to cause disease in humans. Gaining insight into how bacteria maintain homeostasis when in magnesium deficient environments will provide critical knowledge in finding new treatments for antibiotic resistant bacteria. Through a genetic screen, we have identified a novel periplasmic lipoprotein of unknown structure and biochemical function that rescues growth of a mutant strain of Salmonella enterica that is unable to respond to magnesium deficient environments. Interestingly, this lipoprotein has a single domain of unknown function that is conserved among a large number of disease causing enteric bacteria. To elucidate the structural characteristics of the protein, circular dichroism (CD) and X‐ray crystallography techniques are being used. CD experiments have revealed that the protein is composed primarily of beta‐sheet secondary structure, which confirms the secondary structure predicted by homology modeling. Thermal denaturations analyzed by CD reveal a single state reversible transition with a melting temperature of approximately 71 °C. Additionally, we are progressing towards obtaining the first high resolution atomic structure of this protein. We have developed reproducible crystal conditions for the native protein and have successfully obtained atomic resolution X‐ray diffraction data which suggests more than one monomer per asymmetric unit. Initial attempts at molecular replacement with this data have so far been unsuccessful. Selenomethionine (SeMet) was incorporated into the native protein, and has also been successfully crystallized. Obtaining X‐ray diffraction data on these crystals will provide the phasing information necessary to solve the first atomic resolution structure of this protein. The structure will ultimately provide us with knowledge of this protein's role in magnesium homeostasis within Salmonella.Support or Funding InformationThis work was supported by the University of Wisconsin‐ La Crosse Undergraduate Research and Creativity grant (DR), McNair Scholars program (DR), and a University of Wisconsin‐ La Crosse Faculty Research grant (JM). The authors would also like to thank Professor James Keck (University Wisconsin, Department of Biomolecular Chemistry) for allowing access to the Advanced Photon Source. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE‐AC02‐06CH11357. Use of the LS‐CAT Sector 21 was supported by the Michigan Economic Development Corporation and the Michigan Technology Tri‐Corridor (Grant 085P1000817). GM/CA@APS has been funded in whole or in part with Federal funds from the National Cancer Institute (ACB‐12002) and the National Institute of General Medical Sciences (AGM‐12006).

A portfolio decision analysis approach to support energy research and development resource allocation

Research sponsored by the US Department of Energy (DOE) aims to facilitate a clean and independent energy future for the nation. Strategic planning for energy research and development (R&D) can be complex and dynamic, in part due to federal budgetary constraints and volatility. Managing R&D funding to advance energy technologies, in spite of these challenges, is a crucial component of the nation's long term energy policy. This study demonstrates a portfolio decision analysis (PDA) approach to support R&D resource allocation decisions for the DOE Office of Fossil Energy's Carbon Capture and Storage R&D program. A multi-attribute value model uses technology readiness levels (TRLs) and other metrics to represent the overall objectives of the R&D program in order to evaluate alternative research portfolios given limited funding. Mathematical optimization identifies efficient funding allocations for each technology program area to maximize the multi-attribute value generated from the total budget. This is especially useful for responding to externally imposed budget changes. As the case study demonstrates, explicitly funding the most value-generating options leads to greater expected R&D programmatic value than typical strategies of equal or proportional distributions of a budget change among technology program areas.

United States Department of Energy Severe Accident Research Following the Fukushima Daiichi Accidents

The U.S. Department of Energy (DOE) has played a major role in the U.S. response to the events at Fukushima Daiichi. During the first several weeks following the accident, U.S. assistance efforts were guided by results from a significant and diverse set of analyses. In the months that followed, a coordinated analysis activity aimed at gaining a more thorough understanding of the accident sequence was completed using laboratory-developed, system-level best-estimate accident analysis codes, while a parallel analysis was conducted by U.S. industry. A comparison of predictions for Unit 1 from these two studies indicated significant differences between MAAP and MELCOR results for key plant parameters, such as in-core hydrogen production. On that basis, a crosswalk was completed to determine the key modeling variations that led to these differences. In parallel with these activities, it became clear that there was a need to perform a technology gap evaluation on accident-tolerant components and severe accident analysis methodologies with the goal of identifying any data and/or knowledge gaps that may exist given the current state of light water reactor (LWR) severe accident research and augmented by insights from Fukushima. In addition, there is growing international recognition that data from Fukushima could significantly reduce uncertainties related to severe accident progression, particularly for boiling water reactors. On these bases, a group of U.S. experts in LWR safety and plant operations was convened by the DOE Office of Nuclear Energy (DOE-NE) to complete technology gap analysis and Fukushima forensics data needs identification activities. The results from these activities were used as the basis for refining DOE-NE's severe accident research and development (R&D) plan. This paper provides a high-level review of DOE-sponsored R&D efforts in these areas, including planned activities on accident-tolerant components and accident analysis methods.

Berichtigung: Programming A Molecular Relay for Ultrasensitive Biodetection through 129Xe NMR

Die Danksagung in dieser Zuschrift muss wie folgt lauten: “This work was supported by NIH R01-GM097478 and CDMRP-LCRP Concept Award no. LC130824. The ITC was purchased via NIH S10-DO016260. We thank Drs. George Furst and Jun Gu for assistance with NMR spectroscopy. We thank Dr. David Christianson for the CAII plasmid and assistance with crystallography. This work is based upon research conducted at the Northeastern Collaborative Access Team beamlines, which are funded by the National Institute of General Medical Sciences from the National Institutes of Health (P41 GM103403). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. The SSRL Structural Molecular Biology Program is supported by the DOE Office of Biological and Environmental Research, and by the National Institutes of Health, National Institute of General Medical Sciences (including P41GM103393).”

Corrigendum: Programming A Molecular Relay for Ultrasensitive Biodetection through 129Xe NMR

The acknowledgement section in this Communication should read as follows. “This work was supported by NIH R01-GM097478 and CDMRP-LCRP Concept Award no. LC130824. The ITC was purchased via NIH S10-DO016260. We thank Drs. George Furst and Jun Gu for assistance with NMR spectroscopy. We thank Dr. David Christianson for the CAII plasmid and assistance with crystallography. This work is based upon research conducted at the Northeastern Collaborative Access Team beamlines, which are funded by the National Institute of General Medical Sciences from the National Institutes of Health (P41 GM103403). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. The SSRL Structural Molecular Biology Program is supported by the DOE Office of Biological and Environmental Research, and by the National Institutes of Health, National Institute of General Medical Sciences (including P41GM103393).”

Resolving Active Sites and Porosity in PGM-Free Catalysts By Electron Microscopy

Electrodes based on platinum group metal-free (PGM-free) catalysts are under development as an alternative to costly Pt-based cathodes for automotive fuel cell systems.[1,2] Novel PGM-free catalysts with much improved activity and durability must be developed in order to become competitive with their PGM nanoparticle counterparts for transportation applications. Analytical characterization by transmission electron microscopy plays an important role in identifying electrochemically active sites at the atomic scale as well as to exploring electrode morphology and porosity at the microscale. In this work, a hybrid PGM-free catalyst developed at Los Alamos National Laboratory was studied by multiscale and multidimensional electron microscopy methods. This promising catalyst, branded CM-PANI-Fe-C, has been synthesized by heat-treating two nitrogen precursors, polyaniline (PANI) and cyanamide (CM). The catalyst is comprised of fibrous carbonaceous agglomerates intermixed with few-layer graphene sheets. Low voltage aberration-corrected scanning transmission electron microscopy (STEM) and atomic resolution electron energy loss spectroscopy (EELS) were utilized to identify single Fe atoms coordinated with nitrogen within the few-layer graphene sheets (Fig. 1a,b). These atomic features have been identified by modeling as a possible active site which exhibits high four-electron selectivity. The thick electrode structures required to accommodate high non-PGM loadings also play a critical role in fuel cell performance. Hierarchal pore structures (spanning the micro to macro) are necessary for maintaining high mass transport through the thick electrodes. Complementary imaging and compositional mapping by energy dispersive X-ray spectroscopy (EDS) has been utilized to study the bulk electrode structures, as shown in Fig. 1c. These analytical studies will be extended to understand the role of different process parameters on catalyst and electrode structures at multiple length scales. References G. Wu, K. L. More, C. M. Johnston, P. Zelenay, Science 332 (2011) 443.Z. Chen, D. Higgins, A. Yu, L. Zhang, J. Zhang, Energy Environ. Sci. 4 (2011) 3167. Acknowledgements Research sponsored by the Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy (DOE), and through a user project supported by ORNL’s Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. Figure 1

Non-Isothermal Aging of Lithium-Ion Cells

Lithium-ion batteries are rapidly being adopted for transportation applications, ranging from hybrid- to full-electric vehicles. To assure that the automotive battery can meet the demands of these applications, the US Advanced Battery Consortium has established test manuals and performance targets for each application [1-3]. These manuals use accelerated tests to gather needed performance degradation information in a limited amount of time. Models are then developed from these data that relate performance decline to the magnitude and duration of the stress. Isothermal aging stresses the battery under a simple set of conditions and can be used to elucidate the underlying degradation mechanisms. It is then generally assumed that a cumulative degradation model of aging under non-isothermal conditions would be a linear combination of the isothermal results. However, this approach may not directly predict the non-isothermal behavior. A model based on degradation rates may be a better predictor. In theory, integrating the rate-based model over the temperature path can then express the cumulative degradation. The results of this investigation will be discussed. The work at Argonne National Laboratory was performed under the auspices of the U.S Department of Energy (DOE), Office of Vehicle Technologies, under Contract No. DE-AC02-06CH11357. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. The efforts at Idaho National Laboratory and at Lawrence Berkeley National Laboratory were performed under Contract Numbers DE-AC07-05ID14517 and DE-AC03-76SF00098, respectively.This article issue has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (Argonne). Argonne, a DOE Office of Science Laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up, nonexclusive, irrevocable, worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. References FreedomCAR Battery Test Manual for Power-Assist Hybrid Electric Vehicles, DOE/ID-11069, October 2003.Battery Test Manual for Plug-In Hybrid Electric Vehicles, Rev. 3, INL/EXT-14-32849, September 2014.Battery Test Manual for Electric Vehicles, INL/EXT-15-34184, Rev. 3, June 2015

Selective Yield of the Distorted Fe-N4-Cx Active Site with Immunity for Anion Poisoning for Oxygen Depolarized Cathode Applications

Engendering anion immunity has tremendous implications in electrocatalysis in aqueous acidic electrolytes. This is specially exemplified by oxygen reduction reaction and its connotations with application for energy conversion (phosphoric acid), oxygen depolarized cathodes (ODC) (HCl recovery) and metal air batteries. For ODC cathodes used for chlorine generation, it is noteworthy that an energy saving of ~700 kWh per ton of chlorine gas (up to 30%) can be realized. Need for immunity for anion poisoning is particularly manifest as a result of dependence on costly and rare platinum group metal (PGM) catalysts considering their vulnerability to impurities such as halides. In this abstract we will demonstrate a new class of pyrolyzed M-Nx-C (M=Fe and/or Co) catalysts, which are immune to anion poisoning and are the leading non-platinum group metal (non-PGM) catalysts for ORR owing to their high activity and stability. Unique aspect of these emanates from the use of metal organic framework (MOF) precursors such as Zn based zeolitic imidizolate framework (ZIF, a subclass of metal organic framework) as a sacrificial template1. Herein, we report a facile, low cost and scalable synthetic process of ZIF-8 using a reactive ball-milling approach. A highly active Fe-based ORR catalyst using the as-synthesized ZIF-8 as precursor is demonstrated in hydrochloric acid electrolysers. The ZIF-8 derived catalyst shows a prominent ORR activity with an on-set potential of 0.92 V and a half wave potential of 0.78 V in 0.1 M HClO4 electrolyte in the rotating disk electrode (RDE). The high ORR activity can be partly attributed to the ultra-high surface area as it is closely related to the high density of active sites and the intrinsically improved mass transport properties of the MOF. In addition, combined x-ray adsorption spectroscopy (XAS) and Mössbauer spectroscopy reveal that this catalyst contains high concentration of the distorted Fe-N4-Cx moiety featured with a large Fe out-of-plane displacement and elongated Fe-N bond distance, which is shown to exhibit high intrinsic activity toward ORR owing to the moderate Fe-O binding energy and high Fe2+/3+ redox transition potential.2 Remarkably, the highly active ORR catalyst sustains its activity even in presence of high concentrations of Cl- (Fig. 1), thereby opening up promising avenues for the application of Fe-Nx-C catalysts such as ODCs in hydrochloric acid recovery electrolyzers (Fig. 2). Acknowledgement The authors gratefully acknowledge financial support from the Massachusetts Clean Energy Council via their catalyst award (2013). The authors also gratefully acknowledge the financial support from Denora North America (2014). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of Beamline 2-2 at SSRL was partially supported by the National Synchrotron Light Source II, Brookhaven National Laboratory, under U.S. Department of Energy Contract No. DE-SC0012704. Use of the beamline 9-BM in Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Use of Hybrid Cathodes to Reduce Platinum Content in High Temperature Proton Exchange Membrane Fuel Cells (HT-PEMFCs)

An investigation into the development and use of hybrid cathodes in high temperature proton exchange membrane fuel cells was undertaken. Previously, non-pgm materials had been developed for use as oxygen reduction catalysts in proton exchange membrane fuel cells[1, 2]. Compared to platinum, long term durability of these non-pgm materials at the elevated temperatures associated with high temperature fuel cells is negatively impacted by the low active site density. In this work, these non-pgm materials are combined with low platinum loadings in order to take advantage of the high activity of the non-pgms as well as the high active site density of platinum. This reduction of platinum content allows for a drastic reduction in the price of membrane electrode assemblies (MEAs). Additionally, these non-pgm materials have shown very high tolerance towards phosphate poisoning (Figure 1) when compared to platinum[3]. Hybrid cathodes were fabricated and used in conjunction with proprietary membranes (TPS Membrane, Advent Technologies) and operated between 160°C and 180°C in order to evaluate performance and stability. Acknowledgment: The authors gratefully acknowledge the financial support from the Department of Energy-Energy Efficiency and Renewable Energy, Fuel Cell Technology Office under an Incubator grant (DE-EE0006965). Use of the Stanford Synchrotron Radiation Light source, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of Beamline 2-2 at SSRL was partially supported by the National Synchrotron Light Source II, Brookhaven National Laboratory, under U.S. Department of Energy Contract No. DE-SC0012704. Use of the beamline 9-BM in Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Understanding the Enhanced Activity of Pt-Alloys Toward Hydrogen Oxidation Reaction in Alkaline Media

Recent advances in anion exchange membranes (AEMs) and catalysts with greatly improved ORR kinetics are tempered by the two orders of magnitude higher overvoltages for the hydrogen oxidation/evolution reaction (HOR/HER) rates as compared to acidic pH. It has been demonstrated that Pt in conjunction with additional transition metalsm (Pt-M), either alloyed or as an ad-atom exhibit enhanced HOR activity in high pH media compared to pure Pt. However, the mechanistic origin of the activity enhancement induced by the second metal has been under extensive debate and remains unclear. Some researchers propose that the enhanced HOR activity exhibited by Pt-M is attributable to the bifunctional effects whereby optimal interaction energies of adsorption/dissociation of H2 and adsorption of hydroxyl species (OHad) on metal surfaces are achieved;1 whereas others argue that the Pt-H binding energy is the dominant factor determining the HOR activity of Pt-alloys in alkaline media.2 Herein, a series of nanoscale Pt-alloys including PtRu/C, PtNb/C, and PtCo/C with various composition and particle morphology were investigated by rotating disk electrode testing and surface-sensitive in situ x-ray absorption spectroscopy (XAS) method. In an attempt to fully rationalize all the experimental results, we propose a fundamentally novel rendition of the electrochemical double-layer structure wherein the hydroxide-species formed in the compact part of the double-layer, either on an adjacent non-precious alloying metal (-OHad in the Inner Helmholtz Plane of the double-layer) or on the precious metal (-OHad in the Outer Helmholtz Plane of the double-layer), plays an important role in enhancing HOR kinetics at high pH media. A complex relationship, heretofore unknown, exists between electrocatalysis and the electrochemical double-layer structure which will unraveled here in more detail with both theoretical and experimental results. Acknowledgements: The authors gratefully acknowledge the financial support from Arpa-e, US DOE under a grant lead by Proton On-Site, Walingford, CT. Use of the Stanford Synchrotron Radiation Light-source, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of Beamline 2-2 at SSRL was partially supported by the National Synchrotron Light Source II, Brookhaven National Laboratory, under U.S. Department of Energy Contract No. DE-SC0012704. Use of the beamline 9-BM in Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. References (1) Strmcnik, D.; Uchimura, M.; Wang, C.; Subbaraman, R.; Danilovic, N.; van der, V.; Paulikas, A. P.; Stamenkovic, V. R.; Markovic, N. M. Nat Chem 2013, 5, 300. (2) Durst, J.; Siebel, A.; Simon, C.; Hasche, F.; Herranz, J.; Gasteiger, H. A. Energy & Environmental Science 2014, 7, 2255. Figure 1

Investigation of Structural Dynamics in Lithium Layered Oxide Positive Electrodes Via Coherent Diffraction Imaging

The need to increase energy density in the layered oxide positive electrode materials has lead to a push to higher voltages.1 However, as a consequence of these higher voltages, the cycle stability drops considerably due to lattice contraction, electrode surface reactions with the electrolyte, and related strain. The lithium-excess layered oxides, a subset of layered oxide materials, exhibit one of the highest capacities in positive electrode materials due to the addition of anion redox pairs to compensate the charge mechanism2. While promising, this material also suffers from thermodynamic instabilities and surface transformations when charged to higher voltages, necessary to utilize its full capacity3. Operando coherent X-ray diffraction is an eloquent technique that has provided information in the nonequilibrium structural dynamics at the single particle level in lithium battery spinel positive electrode materials4. In addition, through phase retrieval algorithms, three-dimensional defect dynamics can also be determined to understand the nanoscale mechanisms during high voltage cycling5,6. In this study, we apply the same principles to the lithium excess layered oxide, Li1.2Ni0.133Mn0.533Co0.133O2where a plateau can be observed for the Li-rich material at 4.5 V that correspond to a simultaneous extraction of lithium and oxygen. Figure (Left) illustrates powder diffraction at the (003) bragg peak during electrochemical cycling illuminating ~ 20 individual particles where they can be found at relatively high and low angles during the plateau region. Figure 2(right) is the corresponding single particle diffractive imaging for two different primary particles of the same material. Interestingly, an inhomogeneous structural evolution during the first charge occurs where some particles shows a delay before moving to lower angles. Acknowledgements This work was supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-SC0001805. Y.S.M., S.H. and H.L. acknowledge the support by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231, Subcontract No. 7073923, under the Advanced Battery Materials Research (BMR) Program. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. (1) Liu, W.; Oh, P.; Liu, X.; Lee, M.-J.; Cho, W.; Chae, S.; Kim, Y.; Cho, J. Angew. Chem. Int. Ed. 2015, n/a. (2) Yu, H.; Zhou, H. J. Phys. Chem. Lett. 2013, 4, 1268. (3) Xu, B.; Fell, C. R.; Chi, M.; Meng, Y. S. Energy & Environmental Science 2011, 4, 2223. (4) Singer, A.; Ulvestad, A.; Cho, H. M.; Kim, J. W.; Maser, J.; Harder, R.; Meng, Y. S.; Shpyrko, O. G. Nano Lett. 2014, 14, 5295. (5) Ulvestad, A.; Singer, A.; Cho, H. M.; Clark, J. N.; Harder, R.; Maser, J.; Meng, Y. S.; Shpyrko, O. G. Nano Lett. 2014, 14, 5123. (6) Ulvestad, A.; Singer, A.; Clark, J. N.; Cho, H. M.; Kim, J. W.; Harder, R.; Maser, J.; Meng, Y. S.; Shpyrko, O. G. Science 2015, 348, 1344. Figure 1

Understanding Electrocatalyst Morphology, Dispersion, and Stability in Catalyst Layers of PEM Fuel Cells Via 3D Electron Tomography

With the recent development of high-performing Pt-based electrocatalysts, fuel cells for automotive applications are becoming increasingly viable, and understanding the multiple mechanisms contributing to catalyst degradation is a priority to enable further catalyst optimization. In this respect, the 3D structure of the electrocatalyst, catalyst support, and ionomer within actual catalyst layers of membrane electrode assemblies (MEAs) must be fully resolved, complete with compositional profiles, and correlated with the structural and chemical evolution of the material components during fuel cell use. Scanning transmission electron microscopy (STEM)-based tomography methods represent an effective way to interrogate the microstructure of the starting materials (particularly the Pt-based catalysts and carbon supports) and the resulting catalyst layer architectures, despite multiple inherent microscopy challenges, most of which are coupled to long data acquisition times involved and can include beam damage, contamination, insufficient angle collection ranges/increments for the data reconstruction, and the quality of the algorithms employed for producing an accurate tomogram from the tilt series. In addition, varying image contrast levels produced by the different material constituents within the catalyst layer can complicate their specific segmentation for a precise analysis of catalyst dispersion and morphology, pore sizes, ionomer distributions, carbon corrosion, catalyst dealloying/leaching, and catalyst nanoparticle coalescence within the catalyst layer, all of which are important factors contributing to fuel cell degradation. In this work, 3D electron tomography will be used to couple the distinct morphological characteristics of various electrocatalyst and their support structures (e.g., Pt and Pt-allloy catalysts supported on various types of carbon supports) with the resultant nm-scale structures within actual PEM fuel cell catalyst layers. This work will highlight results of 3D STEM-tomography that address the problems of missing wedge artifacts and distinguishing the low contrast of the carbon support from the background. Tilt-series reconstructions of electron energy loss spectroscopy (EELS) and/or energy dispersive X-ray spectroscopy (EDS) elemental maps acquired from the catalyst layers will be presented that provide information regarding porosity and ionomer distributions within catalyst layers as a function of the type of electrocatalyst and catalyst support material employed. Quantifying changes in the structure and composition of the individual materials comprising cathode catalyst layers during fuel cell testing will be similarly evaluated. Research supported by the Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy (DOE) and as part of a user project through Oak Ridge National Laboratory’s Center for Nanophase Materials Sciences, which is a U.S. DOE Office of Science user facility.

Impact of Evolving Electrode Morphology on Fuel Cell Performance: From the Nano to Mesoscale

The performance of polymer electrolyte membrane fuel cells (PEMFCs) is primarily controlled by the materials within membrane electrode assemblies (MEAs), which consist of an anode and cathode separated by a proton-conducting membrane. Developing highly stable MEAs is one key to wide-spread commercialization of this clean energy technology. The electrodes consist of a complex hierarchal structure, which must be capable of simultaneously transporting hydrogen, protons, electrons, oxygen, and water to and way from the critical electrocatalytic active sites. In conventional PEMFCs, Pt serves as the active catalyst, and is sometimes alloyed with a transition metal such as Co or Ni to enhance activity or lower cost.[1] In non-platinum group metal (non-PGM) electrodes, the catalytically active site takes the form of Fe or Co metal-nitrogen-carbon (M-N-C) complexes.[2] In either case, understanding the evolution of these catalysts, and the complex support structures in which they reside, in relation to observed performance losses is essential for furthering fuel cell development. Scanning transmission electron microscopy (STEM) is an ideal analytical characterization tool for performing both pre- and post-mortem nano to mesoscale compositional and structural characterization of the individual material components in MEAs. STEM has been used to quantify key changes responsible for performance gains and losses during fuel cell conditioning and cycling.[3,4] These structural changes can vary widely in both extent and scale, from carbon-corrosion-related electrode thinning at the micron scale to dealloying-induced reordering on the surfaces of advanced Pt-alloy catalysts at the atomic scale. This presentation will focus on three topics spanning multiple length scales in the MEA. Beginning at the atomic scale, strain effects and skeleton structures arising from in situ Ni dealloying in Pt-alloy nanostructured thin films (NSTF) will be presented. The surface structure and composition is critical to electrocatalytic activity, and, as shown by the aberration-corrected Z-contrast STEM image in Fig. 1a, these structures can be resolved with atomic resolution. Changes in surface structure/strain will be studied as a function of fuel cell cycling and electrochemical activity. At the nanoscale, carbon support effects on Pt anchoring and agglomeration will be presented, highlighting the critical role that catalyst-support interactions and corrosion-resistant supports play in MEA durability (Fig. 1b). Finally, at the mesoscale, changes in electrode structure with aging in non-PGM MEAs will be presented, highlighting the key role that hierarchal pore structures (spanning the micro to macro) play in fuel cell performance. Complementary imaging and compositional mapping by energy dispersive X-ray spectroscopy, as shown in Fig. 1c, provide unique insight into how both changes in mechanical and chemical structure impact durability. References V. R. Stamenkovic et al., Nat. Mater. 6 (2007) 241.G. Wu, K. L. More, C. M. Johnston, P. Zeleany, Science 332 (2011) 443.D. A. Cullen et al., J. Mater. Chem. A, 3 (2015) 1660. B. Han et al., Energy Environ. Sci., 8, 258 (2015). Acknowledgements Research sponsored by the Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy (DOE) and ORNL’s Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. Figure 1

Structural and Transport Properties of the Weyl Semimetal NbAs at High Pressure **Supported by the National Natural Science Foundation of China under Grant Nos 11422429 and 11421404, the National Basic Research Program of China under Grant Nos 2012CB821402 and 2015CB921401, the China Postdoctoral Science Foundation under Grant No 2014M560288, the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai

We perform a series of high-pressure synchrotron x-ray diffraction (XRD) and resistance measurements on the Weyl semimetal NbAs. The crystal structure remains stable up to 26 GPa according to the powder XRD data. The resistance of NbAs single crystal increases monotonically with pressure at low temperature. Up to 20 GPa, no superconducting transition is observed down to 0.3 K. These results show that the Weyl semimetal phase is robust in NbAs, and applying pressure may not be a good way to obtain a topological superconductor from Weyl semimetal NbAs.

Iron Dominated 2 T Superconducting Dipoles for the Vertical Section of the FRIB Fragment Separator

The Facility for Rare Isotope Beams under construction at Michigan State University, a new national user facility funded by the U. S. Department of Energy Office of Science will provide exotic rare isotope beams at energies of at least 200 MeV/u at a beam power of 400 kW. The proposed FRIB fragment separator has a preseparator consisting of the hot-cell and vertical section in the first stage followed by two more stages. Two large high performance dipole magnets with a 50 $^{\circ}$ bend are required in the vertical section of the preseparator. Both cost and space constraints in the vertical section along with technical scope have pushed the requirement of the superconducting dipole peak field to 2.0 T. The design of a large magnetic gap (0.2 m), superferric dipole with magnetic rigidity as high as 8 T-m and effective length of 3.49 m is presented. The current design is a “warm iron” H-shaped magnet with nominal yoke length of 3.39 m and magnetic half-gap of 0.10 m. The major challenges are tight spaces in the vertical section, the compact coil and cryostat design and the unbalanced forces. The coil design is based on wet wound epoxy impregnated Formvar insulated conductor that provides ample current and temperature margins. This paper also presents the detailed magnet design including coil forces, coil restraint system, coil properties, conductor stability, quench analysis and full mechanical details.

Budget Malaise May Hit DOE's One Big Growth Area

The Department of Energy office that funds bread-and-butter research with the closest ties to energy and runs the department's big user facilities is facing a budget crunch after years of steady growth.

Process Results for the Integrated Near-Tank Treatment System Pilot Demonstration

The Near-Tank Treatment System (NTTS) is a supplementary waste treatment technology for Hanford tank waste being investigated as part of the Department of Energy Office of Environmental Management's Advanced Remediation Technologies (ART) Program to reduce the number of high-level waste (HLW) canisters that must be processed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The NTTS combines four basic unit operations into one integrated processing plant: caustic leaching, cross-flow filtration, ion exchange, and electrochemical recovery of sodium. Each unit operation has been studied and tested at the bench scale and was combined into a pilot-scale unit for further development. The performance of the Continuous Sludge Leaching (CSL), Near Tank Cesium Removal (NTCR), and NTTS was evaluated by examining the process and analytical data. Overall, the NTTS integrated CSL and NTCR achieved an operational steady state that performed the waste treatment operations for which it was intended. The integrated system was stable and well-controlled, requiring very little manual intervention, and resulted in a product stream which is suitable for downstream sodium recycle, immobilization, and disposal.