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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 OSTI2022

BinFPE

BinFPE is a tool that detects floating-point exceptions (NaN, infinity, and subnormal quantities) in NVIDIA GPU applications using binary instrumentation. It requires no re-compilation of the application and can analyze libraries. The tool extends NVBit (https://github.com/NVlabs/NVBit), which is provided by NVIDIA Labs to analyze binaries. When the tool detects a floating-point exception it reports to the user the location of the exception (file and line number).

Laguna Peralta, Ignacio↗
DOE OSTI2022

XScope

XScope finds inputs that trigger floating-point exceptions, such as NaN (not a number) and infinity, in CUDA functions using Bayesian optimization (BO). XScope assumes that the CUDA functions are a black box, i.e., the source code is not available. It searches the input space using several methods to guide BO into extreme cases. When an input is found to trigger an exception in the target CUDA function, the input is shown to the user.

Laguna Peralta, Ignacio↗
DOE OSTI2025

Soil Temperature and Moisture within the Kougarok Fire Complex, Kougarok Road Mile Marker 86, Seward Peninsula, Alaska, 2019-2023

Daily averages of soil temperature and moisture measured once every hour at different heights located at Intensive Monitoring Stations within the Kougarok Fire Complex, Kougarok Road Mile Marker 86 site. Data were retrieved annually from 2019-2023. Package contains 21 *.CSV data files plus a file level metadata *.CSV, data dictionary *.CSV, data file inventory *.CSV, and sensor location site map *.JPG. Data files have header rows, NaN fields indicate invalid or missing data, and negative vertical offsets are above ground.The Kougarok tundra fire complex (KFC) is located north of Nome and the Kigluaik Mountains, near Quartz Creek and the Kougarok River. The site is accessed by foot from the end of the Nome-Taylor Highway (mile marker 86; also called the Kougarok or Beam Road). The KFC burned in six major fires in the decades since 1950 (Alaska Interagency Coordination Center, unpublished data). Lightning ignited five of these fires (1971, 1997, 2015, and 2019) and one was human caused (2002). The mosaic of overlapping fire scars allows for the study of repeat fires in the tundra which, until recently, was not a common phenomenon outside the boreal forest in Alaska. Our reference unburned tundra fire site is south of the KFC located at mile marker 80 of the Nome-Taylor Highway.The two most recent fires are the Mingvk Lake (2015; 21,698 acres burned from 7/27/2015 to 9/28/2015) and Garfield Creek (2019; 422 acres burned from 7/31/2019 to 8/20/19). The Mingvk Lake fire scar includes areas that burned 1-4x (1971, 1997, 2002), while the entirety of the Garfield Creek fire scar has burned 2x previously (1971, 2002).Previous research at the KFC focused on permafrost (Liljedahl et al. 2007; Narita et al. 2015; Iwahana et al. 2016; Tsuyuzaki, Iwahana, and Saito 2017) and vegetation (Narita et al. 2015; Hollingsworth et al. 2021) response to fire. The central Seward Peninsula is characterized by continuous permafrost with a thickness of 15 to 30 m and a mean active layer thickness of 56 cm (Hinzman et al. 2003). Sloping hills with mixed shrub–tussock tundra and tussock tundra vegetation in the uplands are characteristic of the region. Three micrometeorological towers near the Kougarok field site recorded a mean annual temperature of −2.4°C, mean January temperature of −23.1°C, mean July temperature of +11°C, and mean summer rainfall (June–August) of 94 mm from 2000 to 2006 (Liljedahl et al. 2007).The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research.The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska.Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Materials Data on NaC2N3 by Materials Project

NaN(CN)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Na–N bond distances ranging from 2.40–2.90 Å. In the second Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven N3- atoms. There are a spread of Na–N bond distances ranging from 2.57–2.90 Å. In the third Na1+ site, Na1+ is bonded to six N3- atoms to form distorted edge-sharing NaN6 octahedra. There are a spread of Na–N bond distances ranging from 2.42–3.02 Å. There are six inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.18 Å) and one longer (1.30 Å) C–N bond length. In the second C4+ site, C4+ is bonded in a trigonal planar geometry to three N3- atoms. There are a spread of C–N bond distances ranging from 1.35–1.37 Å. In the third C4+ site, C4+ is bonded in a trigonal planar geometry to three N3- atoms. All C–N bond lengths are 1.36 Å. In the fourth C4+ site, C4+ is bonded in a trigonal planar geometry to three N3- atoms. All C–N bond lengths are 1.36 Å. In the fifth C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.19 Å) and one longer (1.29 Å) C–N bond length. In the sixth C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.19 Å) and one longer (1.30 Å) C–N bond length. There are nine inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted bent 120 degrees geometry to two Na1+ and two C4+ atoms. In the second N3- site, N3- is bonded in a distorted bent 120 degrees geometry to two equivalent Na1+ and two C4+ atoms. In the third N3- site, N3- is bonded in a 4-coordinate geometry to three Na1+ and one C4+ atom. In the fourth N3- site, N3- is bonded in a 4-coordinate geometry to three equivalent Na1+ and one C4+ atom. In the fifth N3- site, N3- is bonded in a 2-coordinate geometry to one Na1+ and two C4+ atoms. In the sixth N3- site, N3- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two C4+ atoms. In the seventh N3- site, N3- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two C4+ atoms. In the eighth N3- site, N3- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two C4+ atoms. In the ninth N3- site, N3- is bonded in a 3-coordinate geometry to two Na1+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaC2N3 by Materials Project

NaN(CN)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Na1+ is bonded to six N3- atoms to form edge-sharing NaN6 octahedra. There are a spread of Na–N bond distances ranging from 2.49–2.57 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.19 Å) and one longer (1.30 Å) C–N bond length. In the second C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.18 Å) and one longer (1.30 Å) C–N bond length. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a rectangular see-saw-like geometry to three equivalent Na1+ and one C4+ atom. In the second N3- site, N3- is bonded in a 3-coordinate geometry to two equivalent Na1+ and one C4+ atom. In the third N3- site, N3- is bonded in a trigonal planar geometry to one Na1+ and two C4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaS2N(O2F)2 by Materials Project

NaN(SO2F)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four ammonia molecules and one NaS2(O2F)2 framework. In the NaS2(O2F)2 framework, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.91 Å. There are two inequivalent S2+ sites. In the first S2+ site, S2+ is bonded in a trigonal non-coplanar geometry to two O2- and one F1- atom. There is one shorter (1.43 Å) and one longer (1.44 Å) S–O bond length. The S–F bond length is 1.60 Å. In the second S2+ site, S2+ is bonded in a trigonal non-coplanar geometry to two O2- and one F1- atom. There is one shorter (1.43 Å) and one longer (1.45 Å) S–O bond length. The S–F bond length is 1.60 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S2+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Na1+ and one S2+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+ and one S2+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and one S2+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one S2+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one S2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaC2S2N(O2F3)2 by Materials Project

NaN(CF3SO2)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of eight ammonia molecules; sixteen fluoroform molecules; and two NaS2O4 sheets oriented in the (0, 0, 1) direction. In each NaS2O4 sheet, there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–2.95 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.42–2.92 Å. There are four inequivalent S2+ sites. In the first S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.45 Å) and one longer (1.46 Å) S–O bond length. In the second S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.45 Å) and one longer (1.46 Å) S–O bond length. In the third S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.44 Å) and one longer (1.46 Å) S–O bond length. In the fourth S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.44 Å) and one longer (1.46 Å) S–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and one S2+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S2+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one S2+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one S2+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one S2+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and one S2+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S2+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one S2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaC2N3 by Materials Project

NaN(CN)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two CN2 ribbons oriented in the (2, 0, 1) direction and two NaCN sheets oriented in the (0, 1, 0) direction. In each CN2 ribbon, C4+ is bonded in a water-like geometry to two N3- atoms. There is one shorter (1.35 Å) and one longer (1.42 Å) C–N bond length. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted bent 120 degrees geometry to one C4+ and one N3- atom. The N–N bond length is 1.25 Å. In the second N3- site, N3- is bonded in a distorted bent 120 degrees geometry to one C4+ and one N3- atom. The N–N bond length is 1.29 Å. In each NaCN sheet, Na1+ is bonded in a 3-coordinate geometry to three equivalent N3- atoms. There are a spread of Na–N bond distances ranging from 2.39–2.78 Å. C4+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. N3- is bonded in a 4-coordinate geometry to three equivalent Na1+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Supporting Special Values in ZFP

This white paper outlines potential approaches to supporting special values in the ZFP numerical compressor without breaking backwards compatibility. Other than infinities and NaNs, special values are often used to indicate the absence of data, where no value is defined, for example by designating finite but extreme “fill values” as special. Such fill values are commonly used in earth system science, among other applications, but if left as is during compression lead to artifacts and loss of precision in nearby true values. Multiple candidate solutions that would allow ZFP to recognize special values are here proposed. Until such support is available, we also sketch available workarounds.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Soil Temperature and Moisture, Council Road Mile Marker 71, Seward Peninsula, Alaska, beginning 2016

Daily averages of soil temperature and moisture measured once every hour at different heights, as well as daily averages of hourly measured snow depths located at Intensive Monitoring Stations at Council Road Mile Marker 71 site. Deployed at each site is an Onset HOBO U30 data logger with five smart temperature sensors and three smart soil moisture sensors (10HS). Three sites (CN_IS_4, CN_IS_6A, CN_IS_7) are equipped with a snow depth sensor. Data are retrieved annually since 2016. Contains 53 *.CSV files including a file inventory list by year. Data files have header rows, NaN fields indicate invalid or missing data, and negative vertical offsets are above ground. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Soil Temperature and Moisture, Teller Road Mile Marker 27, Seward Peninsula, Alaska, 2016-2023

Daily averages of soil temperature and moisture measured once every hour at different heights located at Intensive Monitoring Stations at Teller Road Mile Marker 27 site. Data are retrieved annually from 2016-2023. This is the final update to this dataset: no changes to previous data files with the addition of 2022-2023 data files. Data files have header rows, NaN fields indicate invalid or missing data, and negative vertical offsets are above ground. UPDATED 2025-07: Seven new data files collected in 2022-2023 were added and no previously archived data were changed. This represents the final collection of data and text in the title was changed to reflect the defined timespan. Other files that were added: file-level metadata, a data dictionary, a site location map, and a data file inventory by year. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Soil Temperature and Moisture, Kougarok Road Mile Marker 64, Seward Peninsula, Alaska, beginning 2016

Daily averages of soil temperature and moisture measured once every hour at different heights located at Intensive Monitoring Stations at Kougarok Road Mile Marker 64 site. Data are retrieved annually since 2016. Package contains 46 *.CSV files including a file inventory list by year. Data files have header rows, NaN fields indicate invalid or missing data, and negative vertical offsets are above ground.The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research.The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska.Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Sulfonamide and Sulfonamido-phenol Ligands for Extraction of f-Elements from Alkaline High-Level Waste

Alkaline High Level Waste (HLW) has been accumulated at Hanford and Savannah River Sites as a result of reprocessing for nuclear weapons production during the cold war. A large volume (∼100 MGal) has been accumulated in carbon steel tanks at Savannah River (SRS) and Hanford. The tank waste contains three separate phases generated when NaOH was added to previously acidic Purex raffinates: 1-2 Supernatant liquid, salt-cake, and sludge. The sludge consists mainly of insoluble hydroxides of transition metals while the supernate and salt-cake contain caustic-soluble materials, including salts of highly radioactive fission products Cs(I) and Sr(II). Current treatment of alkaline HLW in SRS includes: i) The Actinide Removal Process (ARP), which is based on sorption of {sup 90}Sr and Actinides (An) on monosodium titanate (MST), also known as 'alpha-strike' process, followed by ii) Caustic Side Solvent Extraction (CSSX),4 which is used for the extraction of {sup 137}Cs by modified calixarenes in a hydrocarbon diluent. Residual actinides in some tanks are removed after CSSX by an additional ARP process commonly referred to as 'alpha-finishing'. Despite the success of ARP for Sr and An removal, as it is a sorption process, it represents the kinetic bottleneck of integrated salt waste processing. Hence potential introduction of additional organic ligands for actinide extraction (in a modified CSSX process) could simplify the overall integrated process, making it more efficient and economical, with less titanate needed and shorter sorption time, as some of the actinide component would be removed during CSSX. In this study tri-sulfonamide and o-sulfonamido-phenol (mono-sulfonamide) ligands have been studied as extractants for Sm(III), which is being used as an Am(III) surrogate. Our prior studies in the group using a tri-sulfonamide (iPr-tsa-B) showed favorable extraction for Sm(III) nitrate salts from alkaline solutions. Mono-sulfonamides possess similar orientation of binding sites to pyrocatechols, which have been found to be good ligands for Am(III) binding and extraction from alkaline media. Tri-sulfonamide of the type iPr-tsa-B6 (1 mM in CH{sub 2}Cl{sub 2} solution) was studied for Ln{sup 3+} extraction using Sm(NO{sub 3}){sub 3}.6H{sub 2}0 (10 and 25 μM) in alkaline solution of NaOH (0.05, 0.1, 0.2, 0.3 mM) / 0.1 M NaNO{sub 3}. Stripping of the organic phase was done using 0.1 M HNO{sub 3} and quantification of Sm{sup 3+} was done using ICP-OES at 359.3 nm. The need to improve stability of the complex led to synthesis of compounds with N-donor site closer to the central benzene ring to facilitate cation-π interactions. Synthesis of tri-sulfonamide type A: a) Chloromethyl methyl ether, SnCl{sub 4}, CH{sub 2}Cl{sub 2}, 0 deg. C, N{sub 2}, 4 h, 57%; b) NaN{sub 3}, reflux in H{sub 2}O/acetone for 22 h, 80%; c) PPh{sub 3}, THF/H{sub 2}O, 22 h, 79%; d) p-toluene sulfonyl chloride, Et{sub 3}N, 1,2-DCE, 22 h. Extraction: Sm(NO{sub 3}){sub 3}.6H{sub 2}O (2 mM) in 5 ml of aqueous NaOH (pH 10.5 - 14) + 6 ml of CH{sub 2}Cl{sub 2} solution of msa (20 mole equiv.) were rotated on a wheel (60 rpm; 20 h). Stripping: 5 ml of 0.1 M HNO{sub 3} + CH{sub 2}Cl{sub 2} solution of msa (after extraction, centrifugation and filtration) was rotated on the wheel (60 rpm; 20 h). Sm{sup 3+} was quantified using UV-Visible spectrophotometry.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2026

Effect of H 2 O on the ethylene glycol/alkali dismantling of bagasse for high-value conversion

Using a high-boiling alcohol system to dismantle main components of biomass is a feasible technology. Reducing dismantle operating costs and improving dismantle efficiency are essential for promoting the green, economical, and sustainable development of biomass refining. Therefore, based on the low cost and chemical properties of H 2 O at high temperature, the effects of different H 2 O dosages in NaOH-catalyzed ethylene glycol (HBAA) system on the dismantling efficiency of bagasse, surface lignin coverage, recovered-lignin activity and enzymatic hydrolysis efficiency were investigated. Compared with the HBAA dismantling system without H 2 O, the HBAA system with 60% w/v H 2 O can obviously increase the removal rates of lignin and hemicellulose, while recovering up to 99% of cellulose and significantly declining surface lignin coverage, thus enhancing the enzymatic hydrolysis efficiency. Additionally, the results of density functional theory calculations and 2D HSQC NMR analysis prove that the synergy between H 2 O and ethylene glycol can promote the esterification reaction occurrence at the α-C carbon cation in β-O-4 structure of lignin, thereby protecting the β-O-4 aromatic ether bond. Simultaneously, when the H 2 O dosage increase from 0% to 60%, the enzymatic yield increases from 84.51% to 93.74% with an enzyme load of 10 FPU/g. Based on experimental results, this study conducted a techno-economic analysis of bagasse dismantling for ethanol and co-production of lignin, achieving a minimum ethanol selling price of $\$$1.07 per kg. Here, in this study, a green and economical solution for dismantling the main components of bagasse is developed, which is important for the high-value conversion of bagasse.

Ethylene glycol↗
DOE OSTI2024

Regulation of Electron Cloud Density by Electronic Effects of Substituents to Optimize Photocatalytic H 2 Evolution of Carbon Dots

Carbon dots (CDs) have a wide light absorption range, which are promising candidates for photocatalytic water splitting H 2 evolution, but they show low activity for hydrogen evolution reaction (HER) due to the slow transfer efficiencies of photogenerated carriers. The electron cloud density of photocatalyst is essential for the separation and migration of photogenerated carriers. In this study, the effect mechanism of electron cloud density regulated by the substituents with different electronic effects on the photocatalytic HER of glucose-based CDs is clarified. CDs-SO 3 H and CDs-OH are first obtained by introducing electron-drawing group (–SO 3 H) and electron-donating group (–OH) using a tailoring post-processing strategy. Experimental results show that the H 2 yield catalyzed by CDs-SO 3 H is 89.95 µmol•g –1 in 4 h, which is about four times that of CDs, and 7.4 times that of CDs-OH. The –SO 3 H induces a much negative energy band and high electron cloud density on CDs edges, promoting the separation and transfer of photogenerated carriers; while the CDs-OH exhibits a high positive charge density and an upward energy band, hindering the surface complexation of electron-hole pairs and HER. Furthermore, this study will provide an insight into the design of CDs catalysts with efficient photocatalytic HER at a molecular level.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Li 2 S 6 ‐Integrated PEO‐Based Polymer Electrolytes for All‐Solid‐State Lithium‐Metal Batteries

Abstract The integration of Li 2 S 6 within a poly(ethylene oxide) (PEO)‐based polymer electrolyte is demonstrated to improve the polymer electrolyte's ionic conductivity because the strong interplay between O 2− (PEO) and Li + from Li 2 S 6 reduces the crystalline volume within the PEO. The Li/electrolyte interface is stabilized by the in situ formation of an ultra‐thin Li 2 S/Li 2 S 2 layer via the reaction between Li 2 S 6 and lithium metal, which increases the ionic transport at the interface and suppresses lithium dendrite growth. A symmetric Li/Li cell with the Li 2 S 6 ‐integrated composite electrolyte has excellent cyclability and a high critical current density of 0.9 mA cm −2 at 40 °C. Impressive electrochemical performance is demonstrated with all‐solid‐state Li/LiFePO 4 and high‐voltage Li/LiNi 0.8 Mn 0.1 Co 0.1 O 2 cells at 40 °C.

Fang, Ruyi↗
DOE OSTI2022

Enhancing Li + Transport in NMC811||Graphite Lithium–Ion Batteries at Low Temperatures by Using Low–Polarity–Solvent Electrolytes

LiNi x Co y MnzO 2 (x+y+z=1)||graphite lithium-ion battery (LIB) chemistry promises practical applications. However, its low-temperature (≤ –20°C) performance is poor because the increased resistance encountered by Li + transport in and across the bulk electrolytes and the electrolyte/electrode interphases induces capacity loss and battery failures. Though tremendous efforts have been made, there is still no effective way to reduce the charge transfer resistance (R ct ) which dominates low-temperature LIBs performance. In this work, we propose a strategy of using low-polarity-solvent electrolytes which have weak interactions between the solvents and the Li + to reduce R ct , achieving facile Li + transport at sub-zero temperatures. The exemplary electrolyte enables LiNi 0.8 Mn 0.1 Co 0.1 O 2 ||graphite cells to deliver a capacity of ≈113 mAh g –1 (98% full-cell capacity) at 25°C and to remain 82% of their room-temperature capacity at –20°C without lithium plating at 1/3C. They also retain 84% of their capacity at –30°C and 78% of their capacity at –40°C and show stable cycling at 50°C.

25 ENERGY STORAGE↗