Reversible planar gliding and microcracking in a single-crystalline Ni-rich cathode
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99 GENERAL AND MISCELLANEOUS↗
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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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A Stable Graphitic, Nanocarbon-Encapsulated, Cobalt-Rich Core-Shell Electrocatalyst as an Oxygen Electrode in a Water Electrolyzer
The oxygen electrode plays a vital role in the successful commercialization of renewable energy technologies, such as fuel cells and water electrolyzers. In this study, the Prussian blue analogue-derived nitrogen-doped nanocarbon (NC) layer-trapped, cobalt-rich, core–shell nanostructured electrocatalysts (core–shell Co@NC) are reported. The electrode exhibits an improved oxygen evolution activity and stability compared to that of the commercial noble electrodes. The core–shell Co@NC-loaded nickel foam exhibits a lower overpotential of 330 mV than that of IrO2 on nickel foam at 10 mA cm-2 and has a durability of over 400 h. The commercial Pt/C cathode-assisted, core–shell Co@NC–anode water electrolyzer delivers 10 mA cm-2 at a cell voltage of 1.59 V, which is 70 mV lower than that of the IrO2–anode water electrolyzer. Over the long-term chronopotentiometry durability testing, the IrO2–anode water electrolyzer shows a cell voltage loss of 230 mV (14%) at 95 h, but the loss of the core–shell Co@NC–anode electrolyzer is only 60 mV (4%) even after 350 h cell-operation. The findings indicate that the Prussian blue analogue is a class of inorganic nanoporous materials that can be used to derive metal-rich, core–shell electrocatalysts with enriched active centers.
Sivanantham, Arumugam↗
Atomic-scale mixing between MgO and H2O in the deep interiors of water-rich planets
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99 GENERAL AND MISCELLANEOUS↗
From a Au-rich core/PtNi-rich shell to a Ni-rich core/PtAu-rich shell: an effective thermochemical pathway to nanoengineering catalysts for fuel cells
A major challenge for the design of noble metal nanocatalysts is the ability of surface engineering to enhance the activity and stability with minimum use of the noble metals.
Chemistry↗
Techno-economic analysis and life-cycle analysis of two light-duty bio-blendstocks: isobutanol and aromatic rich hydrocarbons
Isobutanol and aromatic-rich hydrocarbons (ARHC) are two biomass-derived high octane blendstocks that could be blended with petroleum gasoline for use in optimized spark-ignition engines in light-duty vehicles, potentially increasing engine efficiency. To evaluate technology readiness, economic viability, and environmental impacts of these technologies, we use detailed techno-economic analysis (TEA) and life-cycle analysis (LCA). We assumed isobutanol is produced via biochemical conversion of an herbaceous feedstock blend while ARHC is produced via thermochemical conversion of a woody feedstock blend.The minimum estimated fuel selling price (MFSP) of isobutanol ranged from $5.57/gasoline gallon equivalent (GGE) based on today’s technology to $4.22/GGE with technology advancements. The MFSP of ARHC could decline from $5.20/GGE based on today’s technology to $4.20/GGE as technology improves. Both isobutanol and ARHC offer about 73% GHG emission reduction relative to petroleum gasoline per LCA of these two bio-blendstocks. On the other hand, water consumption in the production of both bio-blendstocks exceeds that of conventional gasoline although process engineering offers routes to cutting water consumption. Over their life cycles, both isobutanol and ARHC emit more NOx and PM2.5 than petroleum gasoline.Improving the energy efficiency and lowering air emissions from agricultural equipment will reduce the life-cycle air pollutant emissions of these bio-blendstocks.
techno-economic analysis, life-cycle analysis, bio↗
J-type Carbon Stars: A Dominant Source of 14 N-rich Presolar SiC Grains of Type AB
Here, we report Mo isotopic data of 27 new presolar SiC grains, including 12 14 N-rich AB ( 14 N/ 15 N > 440, AB2) and 15 mainstream (MS) grains, and their correlated Sr and Ba isotope ratios when available. Direct comparison of the data for the MS grains, which came from low-mass asymptotic giant branch (AGB) stars with large s-process isotope enhancements, with the AB2 grain data demonstrates that AB2 grains show near-solar isotopic compositions and lack s-process enhancements. The near-normal Sr, Mo, and Ba isotopic compositions of AB2 grains clearly exclude born-again AGB stars, where the intermediate neutron-capture process (i-process) takes place, as their stellar source. On the other hand, low-mass CO novae and early R- and J-type carbon stars show 13 C and 14 N excesses but no s-process enhancements and are thus potential stellar sources of AB2 grains. And because both early R-type carbon stars and CO novae are rare objects, the abundant J-type carbon stars (10%–15% of all carbon stars) are thus likely to be a dominant source of AB2 grains.
58 GEOSCIENCES↗
Coupling between oxygen redox and cation migration explains unusual electrochemistry in lithium-rich layered oxides
Abstract not provided
Gent, William E.↗
Constructing “Li-rich Ni-rich” oxide cathodes for high-energy-density Li-ion batteries
The current exploration of high-energy-density cathode materials for Li-ion batteries is mainly concentrated on either so-called “Li-rich” or “Ni-rich” oxides. However, both are suffering from formidable practical challenges. Here, we combine these two concepts to obtain “Li-rich Ni-rich” oxides in pursuit of more practical high-energy-density cathodes. As a proof of concept, we synthesized an array of Li 1+y Ni( 3-5y)/3 Mo 2y/3 O 2 oxides, whose structures were identified to be the coexistence of LiNiO 2 -rich and Li 4 MoO 5 -rich domains with the aid of XRD, TEM, and NMR techniques. Such an intergrowth structure of 5–20 nm size enables excellent mechanical and structural reversibility for the layered rock-salt LiNiO 2 -rich domain upon cycling thanks to the robust cubic rock-salt Li 4 MoO 5 -rich domain enabling an “epitaxial stabilization” effect. As a result, we achieved high capacities (>220 mA h g -1 ) with Ni contents as low as 80%; the Li 1.09 Ni 0.85 Mo 0.06 O 2 member (y = 0.09) shows much improved cycling performances (91% capacity retention for 100 cycles at C/10) compared with pure LiNiO 2 . Further, this work validates the feasibility of constructing Li-rich Ni-rich compounds in the form of intergrowing domains and hence unlocks vast possibilities for future cathode design.
25 ENERGY STORAGE↗
Origin of 16 O-rich fine-grained Ca-Al-rich inclusions of different mineralogy and texture
We conducted a coordinated mineralogical and oxygen isotopic study of four fine-grained calcium-, aluminum-rich inclusions (CAIs) from the ALHA77307 CO3.0 carbonaceous chondrite. Three of the inclusions studied, 05, 1-65, and 2-119, all have nodular structures that represent three major groups, melilite-rich, spinel-rich, and hibonite-rich, based on their primary core mineral assemblages. A condensation origin was inferred for these CAIs. However, the difference in their primary core mineralogy reflects unique nebular environments in which multiple gas-solid reactions occurred under disequilibrium conditions to form hibonite, spinel, and melilite with minor perovskite and Al,Ti-rich diopside. A common occurrence of a diopside rim on the CAIs records a widespread event that marks the end of their condensation as a result of isolation from a nebular gas. An exception is a rare inclusion 2-112 that contains euhedral spinel crystals embedded in melilite, suggesting this CAI had been re-melted. All of the fine-grained CAIs analyzed in ALHA77307 are 16 O-rich with an average Δ 17 O value of ~-22 ± 5‰ (2σ), indicating no apparent correlation between their textures and oxygen isotopic compositions. We therefore conclude that a prevalent 16 O-rich gas reservoir existed in a region of the solar nebula where CO3 fine-grained CAIs formed, initially by condensation and then later, some of them were reprocessed by melting event(s).
58 GEOSCIENCES↗
Designing Principle For Ni-rich Cathode Materials With High Energy Density For Practical Applications
Nickel(Ni)-rich lithium transition metal oxides (e.g. LiNi0.8Co0.15Al0.05O2 (NCA), LiNi1-x-yMnxCoyO2 (x+y<1) (NMC)) with layered structure are regarded as promising cathode candidates for constructing high energy density lithium ion batteries, so as to promote the market penetration of zero-emission electric vehicles. However, the poor structural and interfacial stability of Ni-rich NMC or NCA still hamper their large-scale applications. This review article mainly summarizes the recent progress achieved in the development of Ni-rich cathode materials, with an aim to provide important clues for future design Ni-rich cathodes and eventually enable their practical applications. Firstly, we introduce the improved method for the synthesis of Ni-rich cathode materials and discuss the relationships between the synthesis method, physicochemical properties, and the electrochemical performances of the cathode materials. Secondly, the insightful understandings on the capacity and voltage fading mechanism as well as the reasons of poor structure stability are comprehensively overviewed. Then, we summarize the main progress regarding to the novel approaches and attempts to prolong the cycling lifetime of Ni-rich materials and safety. Finally, we end up this review by proposing new perspectives and insights to stimulate more revolutionary strategies to boost the practical applications of Ni-rich cathodes.
high energy density, Ni-rich materials, modificati↗
Vacancy‐Enabled O3 Phase Stabilization for Manganese‐Rich Layered Sodium Cathodes
Abstract Manganese‐rich layered oxide materials hold great potential as low‐cost and high‐capacity cathodes for Na‐ion batteries. However, they usually form a P2 phase and suffer from fast capacity fade. In this work, an O3 phase sodium cathode has been developed out of a Li and Mn‐rich layered material by leveraging the creation of transition metal (TM) and oxygen vacancies and the electrochemical exchange of Na and Li. The Mn‐rich layered cathode material remains primarily O3 phase during sodiation/desodiation and can have a full sodiation capacity of ca. 220 mAh g −1 . It delivers ca. 160 mAh g −1 specific capacity between 2–3.8 V with >86 % retention over 250 cycles. The TM and oxygen vacancies pre‐formed in the sodiated material enables a reversible migration of TMs from the TM layer to the tetrahedral sites in the Na layer upon de‐sodiation and sodiation. The migration creates metastable states, leading to increased kinetic barrier that prohibits a complete O3‐P3 phase transition.
Xiao, Biwei↗
Design and R&D of RICH detectors for EIC experiments
An Electron-Ion Collider (EIC) has been proposed to further explore the strong force and QCD, focusing on the structure and the interaction of gluon-dominated matter. A generic detector R& D program (EIC PID consortium) for the particle identification in EIC experiments was formed to explore technologically advanced solutions in this scope. In this context two Ring Imaging Cherenkov (RICH) counters have been proposed: a modular RICH detector which consists of an aerogel radiator, a Fresnel lens, a mirrored box, and pixelated photon sensor; a dual-radiator RICH, consisting of an aerogel radiator and C 2 F 6 gas in a mirror-focused configuration. We present the simulations of the two detectors and their estimated performance.
electron-ion collider↗
Proton superfluidity and charge radii in proton-rich calcium isotopes
We report that one of the most important global properties of the atomic nucleus is its size. Experimentally determined nuclear charge radii carry unique information on the nuclear force and complex dynamics of protons and neutrons moving inside the nucleus. The intricate behaviour of charge radii along the chain of Ca isotopes, including the unexpectedly large charge radius of neutron-rich 52 Ca, poses a daunting challenge for nuclear theory. Here we present the measurements of the charge radii of proton-rich isotopes 36,37,38 Ca, whose properties are impacted by the interplay between nuclear superfluidity and weak binding. Calculations carried out within nuclear density functional theory show that the combination of a novel interaction and a state-of-the-art theoretical method can successfully explain the behaviour of charge radii from the lightest to the heaviest Ca isotopes. Lastly, through this model, we show how the new data on 36,37,38 Ca elucidate the nature of nucleonic pairing in weakly bound proton-rich isotopes.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Two New Calcium-rich Gap Transients in Group and Cluster Environments
We present the Palomar Transient Factory discoveries and the photometric and spectroscopic observations of PTF11kmb and PTF12bho. We show that both transients have properties consistent with the class of calcium-rich gap transients, specifically lower peak luminosities and rapid evolution compared to ordinary supernovae, and a nebular spectrum dominated by [Ca ii] emission. A striking feature of both transients is their host environments: PTF12bho is an intracluster transient in the Coma Cluster, while PTF11kmb is located in a loose galaxy group, at a physical offset ∼150 kpc from the most likely host galaxy. Deep Subaru imaging of PTF12bho rules out an underlying host system to a limit of M{sub R}>−8.0 mag, while Hubble Space Telescope imaging of PTF11kmb reveals a marginal counterpart that, if real, could be either a background galaxy or a globular cluster. We show that the offset distribution of Ca-rich gap transients is significantly more extreme than that seen for SNe Ia or even short-hard gamma-ray bursts (sGRBs). Thus, if the offsets are caused by a kick, they require higher kick velocities and/or longer merger times than sGRBs. We also show that almost all Ca-rich transients found to date are in group and cluster environments with elliptical host galaxies, indicating a very old progenitor population; the remote locations could partially be explained by these environments having the largest fraction of stars in the intragroup/intracluster light following galaxy–galaxy interactions.
79 ASTRONOMY AND ASTROPHYSICS↗
Evidence for Reduced, Carbon-rich Regions in the Solar Nebula from an Unusual Cometary Dust Particle
Geochemical indicators in meteorites imply that most formed under relatively oxidizing conditions. However, some planetary materials, such as the enstatite chondrites, aubrite achondrites, and Mercury, were produced in reduced nebular environments. Because of large-scale radial nebular mixing, comets and other Kuiper Belt objects likely contain some primitive material related to these reduced planetary bodies. Here, we describe an unusual assemblage in a dust particle from comet 81P/Wild 2 captured in silica aerogel by the NASA Stardust spacecraft. The bulk of this ∼20 μ m particle is comprised of an aggregate of nanoparticulate Cr-rich magnetite, containing opaque sub-domains composed of poorly graphitized carbon (PGC). The PGC forms conformal shells around tiny 5–15 nm core grains of Fe carbide. The C, N, and O isotopic compositions of these components are identical within errors to terrestrial standards, indicating a formation inside the solar system. Magnetite compositions are consistent with oxidation of reduced metal, similar to that seen in enstatite chondrites. Similarly, the core–shell structure of the carbide + PGC inclusions suggests a formation via FTT reactions on the surface of metal or carbide grains in warm, reduced regions of the solar nebula. Together, the nanoscale assemblage in the cometary particle is most consistent with the alteration of primary solids condensed from a C-rich, reduced nebular gas. The nanoparticulate components in the cometary particle provide the first direct evidence from comets of reduced, carbon-rich regions that were present in the solar nebula.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Li-rich Li[Li1/6Fe1/6Ni1/6Mn1/2]O2 (LFNMO) Cathodes: Atomic Scale Insight on the Mechanisms of Cycling Decay and of the Improvement due to Cobalt Phosphate Surface Modification
Lithium-rich Li[Li1/6Fe1/6Ni1/6Mn1/2]O2(0.4Li2MnO3-0.6LiFe1/3Ni1/3Mn1/3O2, LFNMO) is a new member of the xLi2MnO3·(1-x)LiMO2 family of high capacity - high voltage LIB cathodes. Unfortunately, it suffers from the severe degradation during cycling both in terms of reversible capacity and operating voltage. We are the first to document the corresponding degradation occurring in LFNMO at an atomic scale using aberration- corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) , as well as tracing the elemental crossover to the Li metal anode using XPS. We also demonstrate that a phosphate coating significantly boosts LFNMO cycling stability and rate capability. Due to cycling, the unmodified LFNMO undergoes extensive elemental dissolution (especially Mn) and O loss, forming Kirkendall-type voids. The associated structural degradation is from the as-synthesized R-3m layered structure to a disordered rock-salt phase. Prior to cycling, the phosphate coating shares the crystallography of the parent material. During cycling, a 2-3 nm thick disordered Co-based rock-salt structure is formed on the Mod-LFNMO surface, while the bulk material retains R-3m crystallography. Electrochemical impedance spectroscopy (EIS) analysis highlights how the phosphide treatment stabilizes the charge transfer resistance (RCT), the CEI resistance (RCEI), and the lithium ion diffusion coefficient (DLi). XPS analysis demonstrates that the coating also reduces the amount of cross-over Mn, Fe and especially Ni deposited on the Li metal anode, which is expected to lead to a more stable SEI layer during cycling. These combined cathode - anode findings significantly advance the microstructural design principles for next generation Li-rich cathode materials and coatings.
: high voltage cathode, Li - and Mn - rich cathode↗