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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 OSTI2025

Coal Enhanced PEEK Filament Production for Additive Manufacturing in Industrial Services

The project (Award DE-FE0032146), led by Baker Hughes in collaboration with the University of Wyoming, aims to develop composite PEEK (Polyether-ether-ketone) materials enhanced using coal-derived graphene-based additives suitable for additive manufacturing (3D printing). Coal char (CC), graphene oxide (GO), and reduced graphene oxide (rGO), derived from Powder River Basin (PRB) coal, were successfully integrated into commercial PEEK feedstock. The composite PEEK materials demonstrated tensile and flexural strengths and modulus, Shore hardness, and thermal properties similar to unfilled PEEK. Dielectric strength of 0.5% GO/PEEK is twice that of unfilled PEEK. However, tensile elongation and Izod impact toughness of the composite materials are lower than unfilled PEEK. The 10% CC/PEEK material also shows good recyclability albeit with slightly increased glass transition and cold crystallization temperatures. Filaments of the composite PEEK materials were fabricated using a Filabot system. 3D printing of the composite PEEK initially encountered feeding stoppage caused by the non-uniform diameter of the filament, which was resolved by reducing the nominal diameter from 1.75 to 1.65 mm. The printability of the composite PEEK filaments is limited in geometry and build time, driven by differences in base PEEK feedstock from the commercial PEEK filament at printing conditions. Prototype part printed using the composite filaments shows inconsistent bead width and bead interruption resulting in porosity. Preliminary process and economic evaluation using PRB coal char estimates the cost of GO to be $0.5/lb. Considering the small fraction expected in the composite PEEK, the GO cost is several orders of magnitude lower than the commercial PEEK filament. It is recommended that the printability of composite PEEK filaments to be improved by optimizing the composite PEEK material at the printing conditions and reducing the variations in filament extrusion. Also important is to identify the mechanisms of how coal-derived additives affect the composite PEEK performance and printing characteristics to allow customized material design and processing for target performance.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2020

Effects of graphene surface functionalities towards controlled reinforcement of a lignin based renewable thermoplastic rubber

In this report, we describe methods to enhance mechanical properties of a renewable thermoplastic rubber by incorporating functional graphene platelets into an equal-mass mixture of lignin, a feedstock from plant biomass, and a nitrile-butadiene rubber having 41 mol % acrylonitrile content (NBR41) that form a nanocomposite. Not all lignins yield mechanically strong material when they are combined with NBR41, and thus, limit its use for such rubbery products. Here, we evaluate different graphene oxides (GO) and reduced graphene oxides (rGO) dry-powders with different surface areas, functionality, and wettability in the synthesis of performance-enhanced nanocomposites of soft lignin/NBR41 matrix via a solvent-free, high shear reactive process. High surface area GO (HSGO) platelets with strong hydrophilicity exhibit good dispersion in the multiphase lignin/NBR41 composites with lignin dispersion varying from 200 to 2000 nm, resulting in superior reinforcement over other graphene derivatives. The addition of 1–4 wt % HSGO increased the tensile stress of the lignin/NBR41 thermoplastic rubber matrix by 60–160% (15–24 MPa) and the modulus by 200–700% (60–140 MPa). Scanning electron microscopy and small angle X-ray scattering results show that the well-dispersed HSGO platelets effectively disrupt the lignin-rich aggregates in NBR41 matrix, resulting in both strength and stiffness enhancements in the formed nanocomposites. This report on performance enhancement of lignin-based renewable polymers via the production of nanocomposite would increase potential for ‘finding the value of lignin’—a grand challenge associated with modern biorefineries.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Upgrading of Raw Coal and Coal Waste for Coal-Derived Graphene Process

Conference presentation at 47th International Technical Conference on Clean Energy (Clearwater Clean Energy Conference), Clearwater, Florida, July 23–27, 2023. The University of North Dakota Energy & Environmental Research Center (EERC) conducted a laboratory-scale coal-derived graphene (CDG) project focused on developing a technological process for making graphite from four U.S. domestic coals and coal wastes. Coal and coal waste preprocessing methods were developed and applied to clean and upgrade the coal precursors prior to graphitization and subsequent conversion to graphene products. Carbonization and graphitization of these preprocessed coals and coal wastes has produced graphite, which was used to make graphene oxide (GO) and reduced graphene oxide (rGO). Graphene quantum dots (GQDs) were also made from the raw and upgraded coal precursors.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2021

Definition of a new (Doniach-Sunjic-Shirley) peak shape for fitting asymmetric signals applied to reduced graphene oxide/graphene oxide XPS spectra

The existence of asymmetry in X-ray photoelectron spectroscopy (XPS) photoemission lines is widely accepted, but line shapes designed to accommodate asymmetry are generally lacking in theoretical justification. Here in this work, we present a new line shape for describing asymmetry in XPS signals that is based on two facts. First, the most widely known line shape for fitting asymmetric XPS signals that has a theoretical basis, referred to as the Doniach-Sunjic (DS) line shape, suffers from a mathematical inconvenience, which is that for asymmetric shapes the area beneath the curve (above the x-axis) is infinite. Second, it is common practice in XPS to remove the inelastically scattered background response of a peak in question with the Shirley algorithm. The new line shape described herein attempts to retain the theoretical virtues of the DS line shape, while allowing the use of a Shirley background, with the consequence that the resulting line shape has a finite area. To illustrate the use of this Doniach-Sunjic-Shirley (DSS) line shape, a set of spectra obtained from varying amounts of graphene oxide (GO) and reduced GO on a patterned, heterogeneous surface are fit and discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Coal-based graphene oxide-like materials: A comprehensive review

Coal is the most abundant energy and hydrocarbon resource in the United States which has been primarily used for power generation. With the increasing retirement of coal power plants and transition to a low-carbon emission economy, the future use of coal will likely shift to a feedstock source for production of valuable materials for different applications. In this review, the latest research reported on production of graphene-like materials in a powder form from coal is compiled and discussed. Here, this review includes: 1) brief background information on graphene and related materials (GRM); 2) relevant material, resource, economic, and socioeconomic information regarding suitability of coal as a potential feedstock for production of GRM; 3) a summary of common approaches for coal upgrading for preparation of more suitable precursors for production of GRM; 4) a compilation and analysis of the reported routes and methods for preparation of GRM from coal and coal derivatives; and 5) reported potential applications of coal-based GRM.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Coordinatively and Spatially Coconfining High-Loading Atomic Sb in Sulfur-Rich 2D Carbon Matrix for Fast K + Diffusion and Storage

The atomically dispersed materials promise ultrafast redox kinetics for alkali-ion storage. However, their relatively low mass loading limits their application. In this work, well-dispersed Sb atoms with high-loading of 23.3 wt % anchored in sulfur-rich amorphous carbon-coated reduced graphene oxide matrix (SbSA/C) are prepared by a coordinative and spatial coconfinement methodology including freeze-casting the well-dissolved Sb-chelates (Sb-thioglycolate) within graphene oxide suspension and post heating-treatment. The reduced graphene oxide substrate features open two-dimensional spatial framework for loading atomically dispersive Sb species, and the pyrolyzed Sb-chelates would provide not only massive desirable heteroatoms (S, O) for coordinating the Sb atoms but also in situ pyrolytic carbon for further spatially separating those dispersive atoms. The coordinative and spatial coconfinement engineering also endows the SbSA/C composite with atomic-level Sb atoms against migration and agglomeration during electrochemical K-storage cycling. In situ TEM reveals the uniform potassiation behavior of the SbSA/C without obvious volume change; DFT calculation and electrochemical characterization suggest the significantly lower K-ion diffusion energy barrier. Therefore, on the basis of both the active Sb center and the coordinative heteroatom, the SbSA/C electrode delivers high fast-charging capacity, outstanding rate capability and long-lifespan performance in half/full K-ion batteries (e.g., a stable capacity of 331.3 mA h g –1 is maintained over 1100 cycles at 1.0 A g –1 for half-cell).

36 MATERIALS SCIENCE↗
DOE OSTI2026

Graphene oxide precursor effects on 3D-printed carbon scaffolds

Manganese oxide (MnO 2 ), an earth-abundant material, is a promising component for energy storage devices, with uses in both pseudocapacitors and batteries. However, high MnO 2 loading often leads to reduced performance due to poor ion diffusion. 3D printing, particularly using the direct ink writing (DIW) technique, offers a solution by enabling the fabrication of electrodes with hierarchical porous structures and open channels that enhance mass transport and ion diffusion. Previous work demonstrated that 3D-printed graphene aerogels with MnO 2 coatings exhibited excellent electrochemical performance, even with thick electrodes, due to their optimized structure. Building on this work, the current study investigates the performance differences between aerogels developed using graphene oxide (GO) and reduced graphene oxide (rGO) as carbon precursors. Both materials were incorporated into thixotropic inks, 3D-printed into lattice structures, and carbonized. Despite expected similarities between the final graphene aerogel, rGO-based aerogels exhibited superior areal capacitance, compared to GO-based aerogels. These differences are attributed to the lower oxygen content and defect density of rGO, which influence its interaction with cellulose viscosifiers in the ink formulation. Brunauer–Emmett–Teller (BET) surface area analysis revealed that rGO aerogels exhibit a larger surface area and mesoporous structure, further enhancing their performance. When coated with MnO 2 , rGO-based aerogels maintained their superior capacitive behavior over GO-based aerogels. This study highlights the effect of carbon precursor on the end performance of graphene aerogels.

Materials science↗
DOE OSTI2022

Lepidocrocite Titanate–Graphene Composites for Sodium-Ion Batteries

To overcome electronic transport issues of layered titanates in sodium-ion batteries, we have designed and synthesized composites of lepidocrocite titanates with reduced graphene oxide through a solution-based self-assembly approach. The parent lepidocrocite titanate (K 0.8 [Ti 1.73 Li 0.27 ]O 4 ) was exfoliated by a soft-chemical approach and mechanical shaking. Exfoliated layered titania sheets (LTO) were then combined with reduced graphene oxide (rGO) layers to assemble into composites through flocculation. Countercations (i.e., Mg 2+ ) were used for the self-assembly of negatively charged titania and rGO nanosheets via flocculation. The carbon content in the composites was tuned from 1 to 17% by changing the ratio of titania and rGO sheets in the mixed colloidal suspensions. Electrodes were processed with as-prepared LTO-rGO composites without any carbon additives and tested in sodium half-cell configurations. Mg + -coagulated LTO-rGO composite electrodes deliver higher capacities than electrodes prepared with coagulated titania sheets and 10% acetylene black in sodium half-cells and display good capacity retention after 50 cycles. Electrochemical impedance spectroscopy results indicate lower charge transfer resistance for LTO-14.5%rGO composites than that of coagulated titania sheets with 10% acetylene black. A power law analysis of cells containing the composites indicate a hybrid mechanism consisting of both surface and diffusional processes. A comparison with a similar system, that of dopamine-derived LTO-C heterostructures, reveal significant differences. While capacities showed a strong dependence on carbon content for the dopamine-derived materials, this was not true for the LTO-rGO composites. Instead, the highest capacity was obtained for the 14.5% rGO sample, with a lower value obtained for the 17% rGO sample. A greater proportion of the redox processes were surface rather than diffusional in nature for the LTO-rGO composites as well.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Ordered porous RGO/SnO 2 thin films for ultrasensitive humidity detection

In this work, ordered porous thin films of reduced graphene oxide and tin oxide (rGO/SnO 2 ) were synthesized by a polystyrene sphere monolayer colloidal crystal template method, and their gas-sensing properties were systematically studied. The formed amorphous SnO 2 and partially reduced graphene oxide were analyzed using several complementary material characterization techniques. Further, the results show that the incorporation of rGO significantly improved the humidity sensitivity and the electrical conductivity of the sensor relative to the pristine SnO 2 thin film. Fast response time and excellent selectivity towards humidity were also achieved for the rGO/SnO 2 composite film. The long-term stability of the rGO/SnO 2 sensor was confirmed by comparing its performance to a commercial humidity sensor. The enhanced sensor performance is attributed to the synergistic effects of the incorporation of rGO and the ordered porous structure of the composite film.

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

Large Scale Synthesis of Manganese Oxide/Reduced Graphene Oxide Composites as Anode Materials for Long Cycle Lithium Ion Batteries

Manganese oxides have been frequently used as cathodes in primary batteries. Applications of manganese oxides in secondary batteries are limited by low electrical conductivity and rapid capacity fading because of electrode pulverization and aggregation. In this study, a solid-state synthetic strategy is presented that successfully combines nanosize (~ 50 nm) nickel doped α-MnO 2 with reduced graphene oxides as highly stable composite anodes in lithium ion batteries. The synthesis approach is easy to scale up and suitable for industrial applications. Here, the rationally designed Ni-α-MnO 2 /RGO was tested in galvanostatic half coin cells for Li + charge-discharge studies. The results show that this composite maintains a high capacity of 615 mAh g -1 even after 200 cycles at a high current rate of 1 C (830 mA g -1 ), and with a high Coulombic efficiency near 99%. The anodes exhibit excellent rate capability in a wide range of rate testing from 0.2 to 10 C, without showing capacity decay. This superior anode performance is ascribed to the reduced size of α-MnO 2 domains that are well dispersed in an RGO matrix, which affords good ionic/elec. cond., low charge transfer resistance and mitigates issues of vol. expansion of the anodic active materials. This study opens up an avenue for developing the manufacturing of high-performance electrodes for real applications, such as batteries in electrical vehicles.

25 ENERGY STORAGE↗
DOE OSTI2020

Biomimetic composite architecture achieves ultrahigh rate capability and cycling life of sodium ion battery cathodes

Sodium ion batteries are an emerging candidate to replace lithium ion batteries in large-scale electrical energy storage systems due to the abundance and widespread distribution of sodium. Despite the growing interest, the development of high-performance sodium cathode materials remains a challenge. In particular, polyanionic compounds are considered as a strong cathode candidate owing to their better cycling stability, a flatter voltage profile, and stronger thermal stability compared to other cathode materials. Here, we report the rational design of a biomimetic bone-inspired polyanionic Na3V2(PO4)3-reduced graphene oxide composite (BI-NVP) cathode that achieves ultrahigh rate charging and ultralong cycling life in a sodium ion battery. At a charging rate of 1 C, BI-NVP delivers 97% of its theoretical capacity and is able to retain a voltage plateau even at the ultra-high rate of 200 C. It also shows long cycling life with capacity retention of 91% after 10 000 cycles at 50 C. The sodium ion battery cells with a BI-NVP cathode and Na metal anode were able to deliver a maximum specific energy of 350 W h kg−1 and maximum specific power of 154 kW kg−1. In situ and postmortem analyses of cycled BI-NVP (including by Raman and XRD spectra) HRTEM, and STEM-EELS, indicate highly reversible dilation–contraction, negligible electrode pulverization, and a stable NVP-reduced graphene oxide layer interface. The results presented here provide a rational and biomimetic material design for the electrode architecture for ultrahigh power and ultralong cyclability of the sodium ion battery full cells when paired with a sodium metal anode.

25 ENERGY STORAGE↗