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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Building Durable Multimetallic Electrocatalysts from Intermetallic Seeds

When combined with earth-abundant metals, Pt-based alloy nanoparticles (NPs) can be cost-effective electrocatalysts. However, these NPs can experience leaching of non-noble-metal components under harsh electrocatalytic conditions. In this work, the Skrabalak group has demonstrated a novel NP construct in which Pt-based random alloy surfaces are stabilized against non-noble-metal leaching by their deposition onto intermetallic seeds. These core@shell NPs are highly durable electrocatalysts, with the ability to tune catalytic performance by the core@shell architecture, surface alloy composition, and NP shape. This versatility was demonstrated in a model system in which random alloy (ra-) PtM surfaces were deposited onto ordered intermetallic (i-) PdCu seeds using seed-mediated co-reduction (SMCR). In the initial demonstration, ra-PtCu shells were deposited on i-PdCu seeds, with these core@shell NPs exhibiting higher specific and mass activities for the oxygen reduction reaction (ORR) when compared to similarly sized ra-PtCu NPs. These NPs also showed outstanding durability, maintaining ~85% in specific activity after 5000 cycles. Characterization of the NPs after use revealed minimal loss of Cu. The activity enhancement was attributed to the strained surface that arises from the lattice mismatch between the intermetallic core and random alloy surface. The outstanding durability was attributed to the ordered structure of the intermetallic core. The origin of this durability enhancement was investigated by classical molecular dynamics simulations, where Pt atoms were found to have a lower potential energy when deposited on an intermetallic core than when deposited on a random alloy core. Also, ordering of Cu atoms at the core@shell interface appears to enhance the overall binding between the core and the shell materials. Inspired by this initial demonstration, SMCR has been used to achieve shells of different random alloy compositions, PtM (M = Ni, Co, Cu, or Fe). This advance is significant because ligand effects vary as a function of PtM identity and Pt/M ratio. These features also influence the degree of surface strain imparted from the lattice mismatch between the core and shell materials. Like the initial demonstration, standout features of these core@shell NPs were high durability and resistance to non-noble metal leaching. Moving forward, efforts have been directed toward integrating shape-control to this core@shell NP construct. This integration is motivated by the shape-dependent catalytic performance of NPs derived from the selective expression of specific facets. Considering the initial i-PdCu@ra-PtCu system, NPs with a cubic shape have been achieved by judicious selection of capping ligands during SMCR. Evaluation of these NPs as catalysts for the electrooxidation of formic acid found that the nanocubic shape enhances catalytic performance compared to similar core@shell NPs with a spherical morphology. We envision that SMCR can be applied to other NP systems to achieve highly durable catalysts as the syntheses of monodisperse and shape-controlled intermetallic seeds are advanced. This Account highlights the role of intermetallic cores in providing more durable electrocatalysts. More broadly, the versatility of SMCR is highlighted as a route to integrate architecture, alloy surfaces, and shape within one NP system, and how this achievement is inspiring new high-performance and robust catalysts is discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRSDate not supplied

A Conceptual Architecture for Venus Surface Sample Return

A conceptual architecture for retrieval of a sample of the surface of Venus is proposed. The mission concept incorporates a high-temperature aircraft to retrieve the sample from the surface and raise it into the upper atmosphere, a balloon-borne platform to produce fuel from the carbon dioxide atmosphere of Venus, and a launch vehicle to bring the sample into Venus orbit, where it is retrieved by an Earth-return vehicle.

Venus↗
NASA NTRSDate not supplied

Lagrange-Based Options for Relay Satellites to Eliminate Earth-Mars Communications Outages During Solar Superior Conjunctions

Recent conjunction class Mars human mission plans have generally assumed that there will inevitably be periods of communications outages between Earth and Mars. This has significant cost and risk implications for not only Mars missions, but also precursor missions in the lunar environment. But are there ways to avoid these outages? The potential exists for communications to be interrupted by Solar Superior Conjunctions (SSCs). Depending on the communications system, used, there can be communications outages up to as many as 78 days. The higher bandwidth systems experience the greatest outage. If these communications channels are interrupted due to an SSC, there are of course resulting challenges to mission operations. An outage of a few days to a few weeks could allow minor disturbances to become major concerns or even trigger subsystems failures. An inability to consult with the ground at the wrong time could result in loss of mission, loss of an element, or loss of life. Each planet in the solar system has a set of five Lagrange points associated with it and the Sun. At any given point in time, a planet or either its L4 or L5 point is visible to any other planet in the solar system, regardless of the position of the sun relative to the two. Thus, L4 and L5 have high value as relay systems to prevent communications outages. There are four sets of solar Lagrange points that may be of potential use in this study: Mars-Sun L4 and L5 points, Earth-Sun L4 and L5, Venus-Sun L4 and L5, and Mercury-Sun L4 and L5. A candidate relay satellite system will be identified, with consideration of both new technology developments and existing telecommunications satellites. This system may have implications for not only the Mars human mission architectures, but also Gateway and human lunar surface architectures as these other studies are tasked with paving the way to human Mars missions. If Mars communications outages can be eliminated, then the degree of autonomy necessary in Mars and precursor systems may be reduced.

Relay Satellite↗
NASA NTRS2018

An Affordable Lunar Architecture Emphasizing Commercial and International Partnering Opportunities

Since the cancellation of the Constellation Program, NASA officially has been focused on Mars as the next step for human exploration. Yet many in the space community believe that returning humans to the moon is more logical. Often-cited reasons for this include: (1) should Nature prove to be favorable, the moon could be the basis for expanding the space economy through Off-Earth Mining (OEM) and other commercial endeavors; (2) the moon is scientifically interesting and could serve as a platform for scientific facilities; and (3) useful experience could be gained there for the human journey to Mars. With this in mind, JPL’s A-Team (Architecture Team) was tasked with developing conceptual lunar surface architectures that could simultaneously provide “living on another world” proving ground experience, but would also be affordable and offer truly significant commercial and international partnering opportunities. The task also required that the resulting architectures must eventually lead to and flow seamlessly into planning for human missions to Mars in the 2030s/2040s, if “things go well.” This aspect has been critically missing in other lunar architecture proposals.

Elliott, John↗
NASA NTRSDate not supplied

Uncrewed Lunar Surface Operations and Support Activities

Sustained human presence on the surface of the Moon and future missions to Mars require increased independence from surface crews and Earth-based mission control to operate efficiently, safely, and reliably. The time for surface crews to perform tasks will be limited. Extravehicular activities by surface personnel are burdensome and time-consuming, even when a continuous human presence on the surface occurs. Identifying and balancing human/automation roles and tasks and infusing automation and autonomy practices early in a system’s lifecycle will be essential to achieve mission objectives. Among these objectives are attaining a sustained human presence, improving performance and mission effectiveness, reducing operations and maintenance (O&M) costs, and ensuring operations that are robust to communication delays. To achieve these objectives, an operational shift toward increased automation and autonomy with less reliance on humans is needed. Uncrewed lunar surface operations and support activities occur when surface crews are not present or are independent of surface crew timeline activities requiring no surface crew oversight or intervention. These uncrewed surface opportunities can also be planned to minimize crew workload that avoids routine maintenance and support tasks, thus maximizing crew exploration time. Uncrewed preparations such as staging and prepositioning equipment and materials before the crew arrives could improve crew task efficiency. Additional opportunities exist to conduct uncrewed science, exploration, and utilization. Uncrewed surface architecture functions can include science and exploration; habitation; launch and landing support; surface communication and navigation; surface power generation and distribution; human surface mobility; lifting, handling, manipulating; excavation, construction, and site preparation; logistics management; maintenance and repair; surface resource utilization; integrated site operations and shared support services (e.g., site scheduling/prioritization, dust mitigation/contamination control, and surface safety). Early robotic lunar surface campaigns will provide information on the availability of resources, such as oxygen and water, and demonstrate surface-based technologies. After the Artemis III human lunar return mission, a series of landers will deliver surface systems, cargo, supplies, science packages, spare parts, and commodities. A balance of crewed and uncrewed surface operations will enable a sustained lunar surface presence at the South Pole of the Moon at a site that will be known as the Artemis Base Camp (ABC). It is envisioned that base camp operations on and around the Moon will then help prepare for the mission durations and activities needed to support the first human mission to Mars. Before long-duration crew missions to the base camp can occur, the necessary surface infrastructure will be pre-deployed and verified operational. Surface assets will be teleoperated and remotely managed from Earth. Additionally, robotic and short-duration crewed missions to the ABC will ensure the site’s merit to achieve long-term science objectives, availability of usable resources, and that terrain, seasonal variations, and illumination conditions are acceptable. ABC will consist of different areas where specific functions and services are rendered, including: • Launch and Landing Area • Habitation Area • Power Production Area • Resource Areas Launch and Landing Area—The launch and landing area will support associated functions for the arrival and departure of vehicles, such as crewed landing and ascent and uncrewed cargo deliveries and offloading. It will evolve from an unimproved site at the beginning of the exploration campaign to a more sustainable landing and launch area that can support repeated arrivals and departures. Initial uncrewed Lunar Terrain Vehicle (LTV) surface operations may include emplacement of navigation beacons and communication equipment, real-time video and photography of landing/liftoff events, and element repositioning, such as portable utility power (PUP) (applicable for other landed assets at other areas). Site preparations, such as surface leveling, soil compaction, and berm/path construction, may be needed for a more sustainable launch and landing area capable of accommodating vehicles that are increasingly more reusable and reduce the effects of plume surface interactions and ejecta impacts on nearby surface assets. During the ABC missions, cargo and logistics will be delivered to the lunar surface via robotic cargo landers before the crew arrives. These shipments, which can arrive in pressurized logistics carriers, will deliver the logistics necessary to support a crewed mission and include items such as food, water, equipment spares, etc. Providing the capability to retrieve, offload, and transport the logistics closer to the ABC site before the arrival of the crew will increase the overall efficiency of crew operations once they arrive. In the sustained phase of exploration, other supporting services may be needed, such as lander propellant servicing, surface power services, commodity refreshes, and additional inspection, maintenance, and repair capabilities, to sustain a cadence of extended personnel stays and cargo arrivals and departures. Habitation Area—Uncrewed support to surface habitation could involve supporting activation and pre-entry operations of the habitat while the crew is in orbit at the Gateway outpost preparing for a surface landing. Surface Habitat (SH) uncrewed operations may include bringing the cabin environment to a habitable temperature and air mix and activating other critical crew support systems. Potential crop production uncrewed tasks in the SH could also include autonomous watering and tending. Additionally, when the crew departs, the SH enters dormancy for the long period of uncrewed operation. A logistical staging area could also be collocated near the SH. If so, staging operations for crew supplies, waste re-location, and recycling operations may be opportunities for uncrewed operations. Power Production Area—The Fission Surface Power (FSP) element and its supporting distribution equipment provide power to surface elements as needed across the ABC to supplement day-to-day operations and survive lunar nights. Uncrewed support of this power system includes any initial LTV-assisted deployments of cables and other distributed equipment, associated electrical connections, and system testing and activation operations. Robotically performing some inspections, maintenance, or repair tasks on the power distribution equipment could reduce the surface crew workload. Resource Area— Uncrewed resource prospecting, mapping, and characterizing possible resource sites is likely to be time-consuming and represents an opportunity for uncrewed operations between crewed missions. Uncrewed mobile equipment operations will be needed in the extreme environments of permanently shadowed locations where resource extractions occur. As In-Situ Resource Utilization (ISRU) pilot plant operations begin, uncrewed surface support activities with available mobile and portable assets (LTV, PUP, etc.) will better support these operations. Any produced commodities can be stored at a centralized storage location for future use. Also associated with these operations is the use of mobile robotic excavators for resource acquisition and robotic/autonomous regolith processing. The waste tailings generated during excavation and regolith processing would also need to be transported and deposited at a dedicated location. Surface assets will continue operating between crew visits to maintain surface capabilities, conduct lunar surface science, technology demonstrations, and public outreach opportunities. Additionally, certain sustaining tasks that would consume valuable crew time could be performed before crew arrival, or after their departure. This capability may offer more affordable options to construct, activate, test, and maintain a broad set of surface assets. Telerobotically operated human surface mobility systems, such as the LTV and Pressurized Rover (PR), can be utilized for various tasks. Surface environmental conditions pose a distinct challenge for all these activities. Surface illumination and localized shadows are one such factor. Night-survival operations could consist of thermal management, battery pre-charging, and load shedding. Some surface systems may hibernate through the night and then awake and continue nominal operations. Uncrewed mobile assets may use a more adaptive approach to optimize their power and operations; one method is to follow the sunlight. Night-survival operations may be initiated remotely by teleoperation, automated, or accomplished by supervised autonomous operation. The ability to pre-deploy and control remote assets in orbit or on Mars before the arrival of the mission crew is a key capability that can be simulated on the moon. The base camp provides a venue where these advanced operational concepts, technologies, and autonomous methods and techniques, including the incorporation of time delays to simulate Earth-Mars latency can be replicated to help buy down future Mars mission risks. This paper will examine the evolution of uncrewed lunar surface operations and support activities. It will also discuss the lunar surface environmental conditions (thermal, lighting, terrain, topography, communications) along with the challenges they pose on uncrewed surface operations, and the performance of these activities with limited to minimal human interaction and/or teleoperation. Since lunar missions include Mars mission analogs, such investigation provides the framework for future uncrewed Mars mission support.

Mark E Lewis↗
NASA NTRS2016

Mars Surface Tunnel Element Concept

How Mars surface crews get into their ascent vehicle has profound implications for Mars surface architecture. To meet planetary protection protocols, the architecture has get Intravehicular Activity (IVA)-suited crew into a Mars Ascent Vehicle (MAV) without having to step outside into the Mars environment. Pushing EVA suit don/doff and EVA operations to an element that remains on the surface also helps to minimize MAV cabin volume, which in turn can reduce MAV cabin mass. Because the MAV will require at least seven kilograms of propellant to ascend each kilogram of cabin mass, minimal MAV mass is desired. For architectures involving more than one surface element-such as an ascent vehicle and a pressurized rover or surface habitat-a retractable tunnel is an attractive solution. Beyond addressing the immediate MAV access issue, a reusable tunnel may be useful for other surface applications once its primary mission is complete. A National Aeronautics and Space Administration (NASA) team is studying the optimal balance between surface tunnel functionality, mass, and stowed volume as part of the Evolvable Mars Campaign (EMC). The "Minimum Functional Tunnel" is a conceptual design that performs a single function. Having established this baseline configuration, the next step is to trade design options, evaluate other applications, and explore alternative solutions.

Rucker, Michelle A.↗
NASA NTRS2019

A Permanent Human Lunar Surface Presence Enabled by a CLV Class JUMP Lander

There are compelling advantages of a human presence on the surface of the Moon, as evidenced partly by the preponderance of lunar surface architectures that have existed throughout NASA, industry, and academia since the Apollo program. This paper specifically advocates and illustrates an example of a permanent human lunar surface presence enabled by a commercial launch vehicle (CLV) class Joinable Undercarriage to Maximize Payload (JUMP) lunar lander. The paper will discuss purposes for such a surface presence, including SPD-1 fulfillment, global collaboration, US industry advancement, US government leadership in spaceflight, a Mars dress rehearsal, Mars collaborative exploration, and lunar village development. An architectural description will be presented, including site selection, primary elements, and surface configuration. Element and lander allocation to CLV and Space Launch System (SLS) rockets will be discussed in terms of launch vehicle selection philosophy and allocation to specific launch manifests. This will enable a presentation of a lunar campaign spanning the period from 2026 to 2056. In conclusion, various aspects of the architecture will be suggested for further study.

Howard, Robert L., Jr.↗
DOE OSTI2016

Superhydrophobic and superhydrophilic surface-enhanced separation performance of porous inorganic membranes for biomass-to-biofuel conversion applications

A new class of inorganic-based membranes, i.e., High-Performance Architectured Surface Selective (HiPAS) membranes, is introduced to provide high perm-selective flux by exploiting unique separation mechanisms induced by superhydrophobic or superhydrophilic surface interactions and confined capillary condensation in enlarged membrane pores (~8 nm). The super-hydro-tunable HiPAS membranes were originally developed for the purpose of bio-oil/biofuel processing to achieve selective separations at higher flux relative to size selective porous membranes (e.g., inorganic zeolite-based membranes) and better high-temperature tolerance than polymer membranes (>250 C) for hot vapor processing. Due to surface-enhanced separation selectivity, HiPAS membranes can thus possibly enable larger pores to facilitate large-flux separations by increasing from sub-nanometer pores to mesopores (2-50 nm) for vapor phase or micron-scale pores for liquid phase separations. In this paper, we describe an innovative membrane concept and a materials synthesis strategy to fabricate HiPAS membranes, and demonstrate selective permeation in both vapor- and liquid-phase applications. High permeability and selectivity were demonstrated using surrogate mixtures, such as ethanol-water, toluene-water, and toluene-phenol-water. The overall membrane evaluation results show promise for the future processing of biomass pyrolysis and upgraded product vapors and condensed liquid bio-oil intermediates.

09 BIOMASS FUELS↗
NASA NTRS2009

Power Requirements for The NASA Mars Design Reference Architecture (DRA) 5.0

This paper summarizes the power systems analysis results from NASA s recent Mars DRA 5.0 study which examined three architecture options and resulting mission requirements for a human Mars landing mission in the post-2030 timeframe. DRA 5.0 features a long approximately 500 day surface stay split mission using separate cargo and crewed Mars transfer vehicles. Two cargo flights, utilizing minimum energy trajectories, pre-deploy a cargo lander to the surface and a habitat lander into a 24-hour elliptical Mars parking orbit where it remains until the arrival of the crew during the next mission opportunity approximately 26 months later. The pre-deployment of cargo poses unique challenges for set-up and emplacement of surface assets that results in the need for self or robotically deployed designs. Three surface architecture options were evaluated for breadth of science content, extent of exploration range/capability and variations in system concepts and technology. This paper describes the power requirements for the surface operations of the three mission options, power system analyses including discussion of the nuclear fission, solar photovoltaic and radioisotope concepts for main base power and long range mobility.

Cataldo, Robert L.↗
NASA NTRS2012

Desert Research and Technology Studies Exposure of Lotus Coated Electrodynamic Shield Samples

The passive Lotus dust mitigation coating currently being developed at NASA's Goddard Space Flight Center (GSFC), was selected by the Habitation Demonstration Unit Deep Space Habitat (HDU-DSH) for participation in the 2011 Desert Research and Technology Studies (D-RaTS). Based on the unique surface architecture of the Lotus leaf, the nano-engineered Lotus coating seeks to replicate these structures on space flight and habitation surfaces. By decreasing both the surface energy and area for particle attachment, the Lotus coating greatly diminishes dust accumulation on surfaces. This is a problem that can be encountered on lunar, Martian, and asteroid missions. Two different application methods of this coating were tested in summer 2011 at the D-RaTS site: the wet chemistry applied version and combustion chemical vapor deposition (CCVD) applied version. These Lotus coatings, along with two common thermal control coatings, were combined with the active dust mitigation electrodynamic shield (EDS) technology developed at Kennedy Space Center (KSC). The EDS technology uses an electrified grid to remove dust particles from the surface of a Kapton (Trademark) substrate. The Lotus coating and thermal control coatings were applied to these Kapton (Trademark) substrates for testing. The combination of these two innovations was theorized to be an applicable countermeasure for addressing dust accumulation during long-duration human space exploration. This theory was tested and characterized prior to, during, and after D-RaTS exposure.

Margiotta, Danielle V.↗
DOE OSTI2019

Low-energy helium plasma effects on textured micro-porous tungsten

The effects of low-energy helium plasma on surface evolution and restructuring of micro-porous tungsten and tungsten-rhenium micro-engineered materials was experimentally investigated. Tungsten foam samples of 45 and 80 Pores Per Inch (PPI) of three types of textured surface architecture (nodular W, dense Re-pillars, and W-coated Re-pillars) were exposed to low-energy helium plasma at 80 and 200 eV to fluence levels of 1, 2, and 7 x 10 25 m -2 at 1123 K. The sidewalls of Re pillars exhibited surface holes due to trapped helium while their tips were found to form complex nano-scale web structures, 100's of microns across, rather than nano-tendrils (fuzz) that are often observed in flat W samples. A nano-necklace bead/string structure was observed for the first time on Re pillars, likely driven by a high density of nano-meter size helium bubbles crowded near pillar tips. W-coated Re pillars exhibited typical fuzz nanostructures seen on flat and untextured W-foam, albeit much shorter. While the height of W-fuzz was found to depend on the square root of ion fluence, the nano-web height was found to be linearly dependent on ion fluence. The fuzz was found to grow much slower on nodular foams as compared to planar tungsten, by as much as 25% slower in the W-coated Re pillar samples. Weight loss due to ion sputtering was found to be significantly reduced in nodular foam as compared to planar tungsten, but was found to be more pronounced with Re pillars. Surface coverage by nano-webs may provide insulation against plasma disruptions and act as a passive Thermal Protection System (TPS) that may be ablated during severe plasma disruptions, thus protecting the underlying surface. W-pillars or W-coated Re-pillars are found to allow trapped helium to diffuse out of the surface instead of building up sub-surface stress.

36 MATERIALS SCIENCE↗
NASA NTRS2012

NASA Human Spaceflight Architecture Team: Lunar Surface Exploration Strategies

NASA s agency wide Human Spaceflight Architecture Team (HAT) has been developing Design Reference Missions (DRMs) to support the ongoing effort to characterize NASA s future human exploration strategy. The DRM design effort includes specific articulations of transportation and surface elements, technologies and operations required to enable future human exploration of various destinations including the moon, Near Earth Asteroids (NEAs) and Mars as well as interim cis-lunar targets. In prior architecture studies, transportation concerns have dominated the analysis. As a result, an effort was made to study the human utilization strategy at each specific destination and the resultant impacts on the overall architecture design. In particular, this paper considers various lunar surface strategies as representative scenarios that could occur in a human lunar return, and demonstrates their alignment with the internationally developed Global Exploration Roadmap (GER).

Mueller, Rob P.↗
DOE OSTI2012

Identification of the Major Expressed S-Layer and Cell Surface-Layer-Related Proteins in the Model Methanogenic Archaea: Methanosarcina barkeri Fusaro and Methanosarcina acetivorans C2A

Many archaeal cell envelopes contain a protein coat or sheath composed of one or more surface exposed proteins. These surface layer (S-layer) proteins contribute structural integrity and protect the lipid membrane from environmental challenges. To explore the species diversity of these layers in the Methanosarcinaceae, the major S-layer protein in Methanosarcina barkeri strain Fusaro was identified using proteomics. The Mbar_A1758 gene product was present in multiple forms with apparent sizes of 130, 120, and 100 kDa, consistent with post-translational modifications including signal peptide excision and protein glycosylation. A protein with features related to the surface layer proteins found in Methanosarcina acetivorans C2A and Methanosarcina mazei Goel was identified in the M. barkeri genome. These data reveal a distinct conserved protein signature with features and implied cell surface architecture in the Methanosarcinaceae that is absent in other archaea. Paralogous gene expression patterns in two Methanosarcina species revealed abundant expression of a single S-layer paralog in each strain. Respective promoter elements were identified and shown to be conserved in mRNA coding and upstream untranslated regions. Prior M. acetivorans genome annotations assigned S-layer or surface layer associated roles of eighty genes: however, of 68 examined none was significantly expressed relative to the experimentally determined S-layer gene.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2019

Spacecraft Lighting to Mitigate Microbial Growth

In this innovation project, we investigated the usage of narrow band violet light (408 nm) to attenuate the growth of bacteria typically found on ISS. Violet light is less hazardous than UV light and it can transmit through plastics, such as clear acrylics, making it possible to incorporate into large surface lamps and acrylic or polycarbonate based optical light guides. This study built a custom LED surface panel that was edge lit by an array of 408 nm violet LEDS. The optical light guide technology used in the lamp and the 408 nm violet LEDs are available on the market from multiple vendors. The application of the concept of using violet light driven LED panels and optical light guides is to integrate the paneling into spacecraft architectural surfaces for the automation of a light based microbial countermeasure that could enhance current cleaning methods used in areas on spacecraft prone to microbial growth.

Clark, Toni A.↗
DOE OSTI2022

Unveiling the High-valence Oxygen Degradation Across the Delithiated Cathode Surface

Charge compensation on anionic redox reaction (ARR) has been promising to realize extra capacity beyond transition metal redox in battery cathodes. The practical development of ARR capacity has been hindered by high-valence oxygen instability, particularly at cathode surfaces. However, the direct probe of surface oxygen behavior has been challenging. Here, the electronic states of surface oxygen are investigated by combining mapping of resonant Auger electronic spectroscopy (mRAS) and ambient pressure X-ray photoelectron spectroscopy (APXPS) on a model LiCoO 2 cathode. The mRAS verified that no high-valence oxygen can sustain at cathode surfaces, while APXPS proves that cathode electrolyte interphase (CEI) layer evolves and oxidizes upon oxygen gas contact. In conclusion, this work provides valuable insights into the high-valence oxygen degradation mode across the interface. Oxygen stabilization from surface architecture is proven a prerequisite to the practical development of ARR active cathodes.

25 ENERGY STORAGE↗
DOE OSTI2019

Targeting ultra-high energy neutrinos with the ARIANNA experiment

The measurement of ultra-high energy (UHE) neutrinos (E > 10 16 eV) opens a new field of astronomy with the potential to reveal the sources of ultra-high energy cosmic rays especially if combined with observations in the electromagnetic spectrum and gravitational waves. The ARIANNA pilot detector explores the detection of UHE neutrinos with a surface array of independent radio detector stations in Antarctica which allows for a cost-effective instrumentation of large volumes. Twelve stations are currently operating successfully at the Moore's Bay site (Ross Ice Shelf) in Antarctica and at the South Pole. In this work, we will review the current state of ARIANNA and its main results. We report on a newly developed wind generator that successfully operates in the harsh Antarctic conditions and powers the station for a substantial time during the dark winter months. The robust ARIANNA surface architecture, combined with environmentally friendly solar and wind power generators, can be installed at any deep ice location on the planet and operated autonomously. We discuss the detector capabilities to determine the neutrino direction by reconstructing the signal arrival direction of a 800 m deep calibration pulser, and the reconstruction of the signal polarization using the more abundant cosmic-ray air showers. Lastly, we describe a large-scale design – ARIA – that capitalizes on the successful experience of the ARIANNA operation and is designed sensitive enough to discover the first UHE neutrino.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Bio-inspired interfaces for easy-to-recycle lithium-ion batteries

The recycling of spent lithium-ion batteries has significant potential to benefit our society economically and environmentally as well as preserving raw materials. Although diverse process chains have been applied or under development to recycle batteries, a common, critical issue for battery recycling is the separation of the metallic current collector from the composite film of the electrode. In this study, inspired by the amazing controllable attachment and detachment ability of geckos’ foot-hairs, microscale near-surface architecture is designed on the interface between the current collector and the composite film in lithium-ion batteries, so that it displays controllable and directional adhesion, i.e., enhanced adhesion can be obtained during its lifetime to cope with the substantial volume changes of the composite film upon intercalation and deintercalation, whereas during recycling, the composite layer of the electrode can be easily peeled off from the current collector in a certain direction. We report this study is the first application of structural adhesives for the development of easy-to-recycle lithium-ion batteries. This technology can also be extended to other electronic products to avoid an ever-growing volume of electronic waste. The fundamental understanding on the interfacial adhesion and delamination mechanisms provides a scientific footing for the realization of next-generation easy-to-recycle electronics.

25 ENERGY STORAGE↗
DOE OSTI2016

Preparation, Structure, and Surface Chemistry of Ni–Au Single Atom Alloys

Ni/Au is an alloy combination that while, immiscible in the bulk, exhibits a rich array of surface geometries that may offer improved catalytic properties. It has been demonstrated that the addition of small amounts of Au to Ni tempers its reactivity and reduces coking during the steam reforming of methane. Herein, we report the first successful preparation of dilute Ni–Au alloys (up to 0.04 ML) in which small amounts of Ni are deposited on, and alloyed into, Au(111) using physical vapor deposition. We find that the surface structure can be tuned during deposition via control of the substrate temperature. By adjusting the surface temperature in the 300–650 K range, we are able to produce first Ni islands, then mixtures of Ni islands and Ni–Au surface alloys, and finally, when above 550 K, predominantly island-free Ni–Au single atom alloys (SAAs). Low-temperature scanning tunneling microscopy (STM) combined with density functional theory calculations confirm that the Ni–Au SAAs formed at high temperature correspond to Ni atoms exchanged with surface Au atoms. Ni–Au SAAs form preferentially at the elbow regions of the Au(111) herringbone reconstruction, but at high coverage also appear over the whole surface. To investigate the adsorption properties of Ni–Au SAAs, we studied the adsorption and desorption of CO using STM which allowed us to determine at which atomic sites the CO adsorbs on these heterogeneous alloys. We find that small amounts of Ni in the form of single atoms increases the reactivity of the substrate by creating single Ni sites in the Au surface to which CO binds significantly more strongly than Au. These results serve as a guide in the design of surface architectures that combine Au’s weak binding and selective chemistry with localized, strong binding Ni atom sites that serve to increase reactivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗