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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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At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Future grid mix impacts on whole-building life cycle assessment

Building construction and operation are a significant contribution to global greenhouse gas emissions, so understanding and mitigating emissions is crucial for reliable and realistic emissions accounting. Whole-building Life Cycle Assessment (WBLCA) is an emissions accounting method that considers lifetime environmental impacts of a building during its construction, operation, and eventual end-of-life. When performing WBLCAs, emission calculations from the building's operation over the entire building lifespan are typically based on today's energy grid mixes. This method does not consider changes or advancements in the clean energy proportion within the grid mix and can over or under-inflate results, skewing the ratio of embodied vs. operational environmental impacts. While a variety of prediction tools estimate what future grid emissions might be, predictions can vary widely. To predict the clean energy ratio within future grid mixes and the potential impact these changes might have on WBLCA, annual data from several existing U.S. grid models was averaged and probabilistic modeling was used to extend the usable projections of shorter forecasts. Results show that clean energy sources will likely continue to increase over time, although the rate of growth varies by model. On average, by 2085, the clean energy penetration of the grid is projected to reach ~81% and renewable energy is projected to reach ~71%, although no widespread consensus is reached. To understand how the future grid mix impacts lifetime building emissions within a WBLCA context, the team analyzed two 2021 IECC-compliant all-electric residential buildings: one built from traditional materials and construction processes and the other built with carbon sequestering materials and modular assembly, with a portion of energy generated on site. The results indicate that a moderate estimate of future electricity grid mixes shows a reduction of yearly operational emissions for traditional residential buildings of 55% between 2025 and 2085, and a corresponding reduction of 48% of total emissions over a 60 year building lifespan. This study offers a nuanced approach to account for the variability of future grid mix models and provides an average trend-line based on a robust collection of scenarios.

Life Cycle Assessment (LCA)↗
NASA NTRSDate not supplied

Pyrolysis Rate and Yield Strength Reduction in Carbon Fiber and Glass Fiber Composites under Reentry Heating Conditions

The behavior of composite materials, specifically carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP), under re-entry conditions poses a problem for orbital debris re-entry risk modeling. Since these materials pyrolyze rather than melt and their different components demise at different rates, modeling their destruction to determine ground impact risk is complex. Modern spacecraft are using these materials in ever-greater quantities owing to their superior strength-to -weight characteristics, and this has required that the orbital debris community improve its understanding of how these materials demise on re-entry.

Benton R Greene↗
DOE OSTI2023

Well-Defined Iron Sites in Crystalline Carbon Nitride

Carbon nitride materials can be hosts for transition metal sites, but Mössbauer studies on iron complexes in carbon nitrides have always shown a mixture of environments and oxidation states. Here we describe the synthesis and characterization of a crystalline carbon nitride with stoichiometric iron sites that all have the same environment. The material (formula C 6 N 9 H 2 Fe 0.4 Li 1.2 Cl, abbreviated PTI/FeCl 2 ) is derived from reacting poly(triazine imide)·LiCl (PTI/LiCl) with a low-melting FeCl 2 /KCl flux, followed by anaerobic rinsing with methanol. X-ray diffraction, X-ray absorption and Mössbauer spectroscopies, and SQUID magnetometry indicate that there are tetrahedral high-spin iron(II) sites throughout the material, all having the same geometry. As a result, the material is active for electrocatalytic nitrate reduction to ammonia, with a production rate of ca. 0.1 mmol cm –2 h –1 and Faradaic efficiency of ca. 80% at −0.80 V vs RHE.

Anions↗
DOE OSTI2021

Investigation of poly(phenylacetylene) derivatives for carbon precursor with high carbon yield and good solubility

This paper investigates a family of poly(phenylacetylene) derivatives with a p-electrons conjugated polymer backbone and side groups containing only sp 2 and sp carbons. The objective is to identify the suitable carbon precursor that is processible and can be transformed to carbonaceous material with high carbon yield by a simple (one-step) thermal transformation process (without any external reagent). Poly(phenylacetylene) with para-substituted acetylene group poly(PA-A) shows an exceptionally high C-yield (~90%) in one-step heating from ambient temperature to 1000 °C under N 2 atmosphere. Unfortunately, this poly(PA-A) polymer is quite sensitive to heat and light with very limited solubility. On the other hand, poly(phenylacetylene) with para-substituted phenylacetylene group, i.e. poly(PA-PA), offers a relatively high C-yield (~80%) and also good solubility in common organic solvents, such as toluene and tetrahydrofuran (THF). Several uniform dark-red poly(PA-PA) fibers with smooth surface and fiber diameter in the range of 3–6 μm were prepared from 30 wt% poly(PA-PA)/THF solution using electrospinning technique. Furthermore, the resulting precursor fibers were converted to the corresponding carbon structure in a one-step thermal heating process under N 2 atmosphere. Both X-ray and Raman spectra show the polymorphous carbon morphology with the graphene crystalline domains.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Spectral and Mineralogical Analyses of Aguas Zarcas in Search of Its Parent Body

Aguas Zarcas is an intriguing carbonaceous chondrite that fell in Aguas Zarcas district, San Carlos, Alajulea, Costa Rica on 23 April 2019 [1]. This carbonaceous chondrite was found to be a breccia at al all scales with diverse lithologies (metal-rich, brecciated CM, and CI) [2]. Here we present spectroscopic and PSD-XRD analyses of a sample of Aguas Zarcas(donated to NASA JSC by Robert Ward) to better understand the origin and parent body for this meteorite. The spectral and mineralogical analyses are placed in the context of the published petrological and geochemical analyses of Aguas Zarcas, and its spectra are compared to a suite of spectra of asteroidal materials, including cabon-bearing asteroids, asteroid returned samples, and carbonaceous chondrites. The focus of this investigation will be on hydrated minerals and carbon-bearing materials, including organics and carbonates.

D. Takir↗
NASA NTRS2001

Computational Nanotechnology of Molecular Materials, Electronics, and Actuators with Carbon Nanotubes and Fullerenes

The role of computational nanotechnology in developing next generation of multifunctional materials, molecular scale electronic and computing devices, sensors, actuators, and machines is described through a brief review of enabling computational techniques and few recent examples derived from computer simulations of carbon nanotube based molecular nanotechnology.

Srivastava, Deepak↗
DOE OSTI2023

Development of coal-derived carbon-based structural unit as a potential new building material

Coal combustion for energy has not only wasted the hydrogen-rich volatile matters but also results in CO 2 emission causing serious environmental issues. An integrated coal pyrolysis and solvent extraction process under elevated temperatures in an inert atmosphere is implemented to convert as-mined coal from Wyoming Powder River Basin to functional carbon elements such as pyrolysis char (PC). This paper presents the development and fabrication of new carbon-based structural unit (CSU) using pulverized PC and two coal-derived pitches (mesophase pitch and tar pitch) to attain high compressive strength greater than 30 MPa, low thermal conductivity less than 0.30 W/m.K, and low density less than 1.25 g/cm 3 . CSUs have the potential to overcome the current challenges with cement and concrete through pressurized fabrication followed by carbonization. This study aims to develop CSU with nearly 100% coal-derived carbon material for structural application in buildings. The effects of pressing pressures, carbonization temperatures, and binder contents on the density and mechanical and thermal properties of CSU samples are investigated. The study concludes that mesophase pitch produces a better performance of CSU samples, a combination of 100 MPa pressing pressure and carbonization temperature of 900 ⁰C yields the highest compressive strength, and a 25% MP content is recommended for low-cost CSU fabrication. Furthermoer, CSU has a much lower density, lower thermal conductivity, higher compressive strength, and higher strength-to-density ratio than normal concrete.

36 MATERIALS SCIENCE↗
NASA NTRS1994

Formation and chemical reactivity of carbon fibers prepared by defluorination of graphite fluoride

Defluorination of graphite fluoride (CFX) by heating to temperatures of 250 to 450 C in chemically reactive environments was studied. This is a new and possibly inexpensive process to produce new carbon-based materials. For example, CF 0.68 fibers, made from P-100 carbon fibers, can be defluorinated in BrH2C-CH = CH-CH2Br (1,4-dibromo-2butene) heated to 370 C, and graphitized to produce fibers with an unusually high modulus and a graphite layer structure that is healed and cross-linked. Conversely, a sulfur-doped, visibly soft carbon fiber was produced by defluorinating CF 0.9 fibers, made from P-25, in sulfur (S) vapor at 370 C and then heating to 660 C in nitrogen (N2). Furthermore, defluorination of the CF 0.68 fibers in bromine (Br2) produced fragile, structurally damaged carbon fibers. Heating these fragile fibers to 1100 C in N2 caused further structural damage, whereas heating to 150 C in bromoform (CHBr3) and then to 1100 C in N2 healed the structural defects. The defluorination product of CFX, tentatively called activated graphite, has the composition and molecular structure of graphite, but is chemically more reactive. Activated graphite is a scavenger of manganese (Mn), and can be intercalated with magnesium (Mg). Also, it can easily collect large amounts of an alloy made from copper (Cu) and type 304 stainless steel to form a composite. Finally, there are indications that activated graphite can wet metals or ceramics, thereby forming stronger composites with them than the pristine carbon fibers can form.

Hung, Ching-Cheh↗
DOE OSTI2020

Carbon electrodes based capacitive deionization for the desalination of water

A capacitive deionization system includes first and second electrodes comprising tire derived carbon particles obtained from a carbonaceous waste-tire source material containing carbon black. A conductive polymer coating on the carbon particles forms coated carbon particles. The first electrode and the second electrode define a flow channel there between, having a first opening for conducting saline solution into the flow channel and a second opening for conducting treated saline solution from the flow channel. A first current collector is provided for the first electrode and a second current collector is provided for the second electrode. An electrical connection between the first and second electrodes. A method of making a system for the capacitive deionization of a salt from a liquid, and a method for the capacitive desalination of a saline solution are also disclosed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Synthesis of high-density olivine LiFePO 4 from paleozoic siderite FeCO 3 and its electrochemical performance in lithium batteries

The lithium-ion cathode material olivine LiFePO 4 (LFP) has been synthesized for the first time from natural paleozoic iron carbonate (FeCO 3 ). The ferrous carbonate starting material consists of the mineral siderite at about 92 wt. % purity. Because FeCO 3 has divalent iron, the reaction with lithium dihydrogen phosphate (LiH 2 PO 4 ) provides a unique method to develop iron-(II) containing LFP in an inert atmosphere. Since siderite FeCO 3 is a common mineral that can be directly mined, it may, therefore, provide an inexpensive route for the production of LFP. After carbon-coating, the LFP yields a capacity in the range of 80–110 mAh g -1 LFP (in one chosen specimen sample), which is lower than commercially available LiFePO 4 (150–160 mAh g -1 LFP ). However, the tap density of LFP derived from siderite is noticeably high at 1.65 g cm -3 . The material is likely to be improved with powder purification, nanosized processing, and more complete carbon-coating coverage with increased optimization.

36 MATERIALS SCIENCE↗
NASA NTRS2006

Transparent and Electrically Conductive Carbon Nanotube-Polymer Nanocomposite Materials for Electrostatic Charge Dissipation

In recent years, nanocomposite materials have been extensively studied because of their superior electrical, magnetic, and optical properties and large number of possible applications that range from nano-electronics, specialty coatings, electromagnetic shielding, and drug delivery. The aim of the present work is to study the electrical and optical properties of carbon nanotube(CNT)-polymer nanocomposite materials for electrostatic charge dissipation. Single and multi-wall carbon nanotubes were grown by catalytic chemical vapor deposition (CCVD) on metal/metal oxide catalytic systems using acetylene or other hydrocarbon feedstocks. After the purification process, in which amorphous carbon and non-carbon impurities were removed, the nanotubes were functionalized with carboxylic acid groups in order to achieve a good dispersion in water and various other solvents. The carbon nanostructures were analyzed, both before and after functionalization by several analytical techniques, including microscopy, Raman spectroscopy, and X-Ray photoelectron spectroscopy. Solvent dispersed nanotubes were mixed (1 to 7 wt %) into acrylic polymers by sonication and allowed to dry into 25 micron thick films. The electrical and optical properties of the films were analyzed as a function of the nanotubes' concentration. A reduction in electrical resistivity, up to six orders of magnitude, was measured as the nanotubes' concentration in the polymeric films increased, while optical transparency remained 85 % or higher relative to acrylic films without nanotubes.

Dervishi, E.↗
DOE OSTI2026

Carbon fiber design improvements based on economic models

Circular fiber geometries are predominant in commercial carbon fiber material systems, but the use of this fiber shape has numerous limitations. Circular geometries have continuous symmetry, which is helpful for various processing considerations, but also have the largest possible maximum diffusion thickness for a given fiber area. This characteristic means that circular carbon fibers always have the highest material processing cost and lowest production throughput compared to any other fiber shape with the same area and tow count. To quantify material cost and other benefits for non-circular carbon fiber geometries, process models for polyacrylonitrile based carbon fiber production are developed in relationship to the carbon fiber shape, size, and tow count. For a given fiber shape, precursor production costs are shown to favor maximizing fiber size while conversion costs are minimized by the smallest fiber size. These competing cost trends result in a numerically optimal fiber size for a given shape and tow count, while both cost components are decreased by increasing tow count. Cost–performance tradeoffs for three lobe fiber geometries are studied by supplementing the cost trends with a numerical failure model to predict compressive strength for discrete shape variants. The shape selection is shown to be more sensitive to variations in cost than compressive strength while suboptimal shape designs can improve manufacturing robustness and achievable fiber volume fractions. Finally, an optimal three lobe carbon fiber is identified that balances the set of considerations while reducing costs and embodied energy and increasing production throughput compared to a commercial carbon fiber.

Carbon fiber↗
DOE OSTI2020

Optical measure of disorder: Why Urbach analysis works for amorphous silicon but fails for amorphous carbon

We investigate the basis for the Paradox where the Urbach-slope disorder parameter disagrees with the Raman width in amorphous diamond-like carbon (DLC) materials (lower Urbach-Eo yet greater Raman width). We examined the bandgap and Urbach-slope measurement issues. While significant errors are identified, ultimately these cannot resolve the Paradox. This resolution involves large changes in shape of DLC's absorption band resulting from large energy shifts. To solidify the understanding of band energy shifts, we examined their properties using a-Si:H, well known for its agreement between Raman and Urbach-slope disorder parameters. Using Tauc-Lorentz (T-L) dispersion functions, the Urbach method works for a-Si:H because small changes in shape occur, as measured by (i) peak position, (ii) peak width, (iii) peak amplitude, and (iv) and gap energies. Moreover, for a-Si:H, a 5th condition (v) there is no other feature below the principal band to interfere with its fall. All 5 of these conditions fail for DLCs. Because T-L dispersions accommodate asymmetry, we traced the Paradox to a steepening of the band shape as it pushes toward lower energy. This steepening is unrelated to disorder, but to a boundary value problem where energy cannot be negative. We conclude that Urbach analysis is invalid for DLC materials, but the T-L width is a good measure instead. We also examined another disorder measure, where π bonds should be considered as disorder relative to the σ bonds in an idealized “amorphous diamond” sp 3 network: superconvergence can be used to quantify these π transitions. Finally, further molecular orbital calculations are needed to properly interpret the changes in T-L widths.

36 MATERIALS SCIENCE↗
DOE OSTI2023

High-Performance, Hybrid Polymer Membrane for Carbon Dioxide Separation from Ambient Air

The Department of Energy (DOE) seeks to develop carbon capture materials specifically tailored for Direct Air Capture (DAC) processes. Related to this, they require recipients to develop novel DAC materials such as: solvents, membranes, or sorbents that demonstrate high affinities or capacities for carbon dioxide (CO2) at concentrations typically available in air and at near ambient conditions. Toward this, InnoSense LLC (ISL) is developing High-Performance, Hybrid Polymer Membranes (HypoMemTM) for Carbon Dioxide Separation from Ambient Air. HypoMem consists of two major layers. The first layer is the active layer which contains the active ingredients that help to separate CO2 from ambient air. The second is the support layer that provides good mechanical support to have a free-standing membrane without interfering with the properties of the active layer.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS2004

Cross-Linked Nanotube Materials with Variable Stiffness Tethers

The constitutive properties of a cross-linked single-walled carbon nanotube material are predicted with a multi-scale model. The material is modeled as a transversely isotropic solid using concepts from equivalent-continuum modeling. The elastic constants are determined using molecular dynamics simulation. Some parameters of the molecular force field are determined specifically for the cross-linker from ab initio calculations. A demonstration of how the cross-linked nanotubes may affect the properties of a nanotube/polyimide composite is included using a micromechanical analysis.

Frankland, Sarah-Jane V.↗
DOE OSTI2023

Microbial production of fuels, commodity chemicals, and materials from sustainable sources of carbon and energy

Anthropogenic carbon emissions are driving rapid changes to the earth's climate, disrupting whole ecosystems and endangering the stability of human society. Innovations in engineered microbial fermentation enable the fossil resource-free production of fuels, commodity chemicals, and materials, thereby reducing the carbon emissions associated with these products. Microorganisms have been engineered to catabolize sustainable sources of carbon and energy (i.e., plant biomass, plastic waste, and one-carbon feedstocks) and biosynthesize carbon-neutral or carbon-negative products. These engineering efforts exploit and optimize natural biological pathways or generate unnatural pathways which can biosynthesize chemicals that have not yet been accessed using synthetic chemistry. Further, recent advances in microbial fermentation seek not only to maximize the titer, rate, and yield of desired products, but also to tailor microbial catabolism to utilize inexpensive feedstocks. Ultimately, these advances aim to lower the cost of bioproduction so that microorganism-derived chemicals can be economically competitive with fossil-derived chemicals.

09 BIOMASS FUELS↗
DOE OSTI2022

Rationalizing nitrogen-doped secondary carbon particles for practical lithium-sulfur batteries

Nanostructured carbon host materials are widely used to improve both sulfur utilization rate and reaction kinetics in lithium-sulfur (Li-S) batteries. However, high complexity/cost of materials synthesis and difficulty in processing nano-materials into high-mass-loading electrodes are still significant barriers to the development of low-cost and high-energy Li-S batteries. In this study, we reported a generic and scalable synthesis approach to prepare nitrogen-doped secondary carbon particles. By using nitrogen-containing precursor as an integration reagent, the nanosized Ketjen Black particles were integrated into micron-size secondary ones and nitrogen-doped (NKB) simultaneously through a one-step heat treatment. With NKB as an example material, the effects of particle integration degree on the secondary particles’ structures, pore volume and connectivity, sulfur loading capability, and cell performance were studied and discussed. At an optimal integration condition, the NKB particles had significantly improved particle dimensions with well-maintained high specific surface area and pore volume. Here, contributed by the micron size and high pore volume, the NKB/S were successfully used for high-sulfur-loading cathodes (4–7 mg s /cm -2 ) and were able to deliver a specific capacity of ~1100 mAh g -1 at a low-porosity (50%) and lean-electrolyte conditions (E/S =4 µL/mg -1 ). Feasibility of the materials for practical use was validated through scaling up synthesis (40 g/batch), large-area electrode coating, and practical pouch cell (1.6 Ah) assembly and test.

25 ENERGY STORAGE↗