Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Mn”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Mn(ReO5)2 by Materials Project

Mn(ReO5)2 crystallizes in the monoclinic C2/m space group. The structure is one-dimensional and consists of two Mn(ReO5)2 ribbons oriented in the (0, 1, 0) direction. Re+6.50+ is bonded to four O2- atoms to form ReO4 tetrahedra that share corners with two equivalent MnO6 octahedra. The corner-sharing octahedral tilt angles are 25°. There is two shorter (1.73 Å) and two longer (1.78 Å) Re–O bond length. Mn7+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four equivalent ReO4 tetrahedra. There are two shorter (1.95 Å) and four longer (2.06 Å) Mn–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Re+6.50+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Re+6.50+ and one Mn7+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Mn7+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Re+6.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(IO2)2 by Materials Project

Mn(O2I)2 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of two Mn(O2I)2 ribbons oriented in the (1, 0, 1) direction. Mn4+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.88 Å) and two longer (1.89 Å) Mn–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one I2+ atom. The O–I bond length is 2.00 Å. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one I2+ atom. The O–I bond length is 2.03 Å. I2+ is bonded in a linear geometry to two O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(PO4)2 by Materials Project

Mn(PO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one Mn(PO4)2 sheet oriented in the (1, 0, 0) direction. Mn7+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Mn–O bond distances ranging from 1.75–2.10 Å. P+4.50+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of P–O bond distances ranging from 1.47–1.51 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one P+4.50+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn7+ and one P+4.50+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn7+ and one P+4.50+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Mn7+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(CuS)2 by Materials Project

Mn(CuS)2 crystallizes in the cubic F-43m space group. The structure is three-dimensional. Mn2+ is bonded in a 9-coordinate geometry to three equivalent Cu1+ and six S2- atoms. All Mn–Cu bond lengths are 2.49 Å. There are three shorter (2.60 Å) and three longer (2.82 Å) Mn–S bond lengths. There are three inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded in a 6-coordinate geometry to two equivalent Mn2+ and four S2- atoms. There are two shorter (2.33 Å) and two longer (2.44 Å) Cu–S bond lengths. In the second Cu1+ site, Cu1+ is bonded in a tetrahedral geometry to four equivalent S2- atoms. All Cu–S bond lengths are 2.37 Å. In the third Cu1+ site, Cu1+ is bonded in a tetrahedral geometry to four equivalent S2- atoms. All Cu–S bond lengths are 2.46 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to three equivalent Mn2+ and four Cu1+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to three equivalent Mn2+ and four Cu1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(CO3)2 by Materials Project

Mn(CO3)2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is two-dimensional and consists of two Mn(CO3)2 sheets oriented in the (0, 0, 1) direction. Mn4+ is bonded to six O2- atoms to form corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 57°. There are a spread of Mn–O bond distances ranging from 1.97–2.29 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.30 Å) C–O bond length. In the second C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.28 Å) C–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn4+ and one O2- atom. The O–O bond length is 1.28 Å. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Mn4+ and one C4+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn4+ and one C4+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn4+ and one C4+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn4+ and one O2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(IO2)2 by Materials Project

Mn(O2I)2 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of two Mn(O2I)2 ribbons oriented in the (1, 0, 1) direction. Mn4+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.88 Å) and two longer (1.89 Å) Mn–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one I2+ atom. The O–I bond length is 1.99 Å. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one I2+ atom. The O–I bond length is 2.00 Å. I2+ is bonded in a linear geometry to two O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(BH4)2 by Materials Project

Mn(BH4)2 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional and consists of two Mn(BH4)2 frameworks. Mn2+ is bonded in a 8-coordinate geometry to eight H+0.50+ atoms. There are a spread of Mn–H bond distances ranging from 2.04–2.22 Å. B3- is bonded in a tetrahedral geometry to four H+0.50+ atoms. There is two shorter (1.23 Å) and two longer (1.24 Å) B–H bond length. There are four inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the third H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the fourth H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to one Mn2+ and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Observation of Topological Spin Textures in Ferrimagnetic Mn 2 − x Zn x Sb

Ferrimagnets, which have both ferromagnetic and antiferromagnetic coupling, are attracting increased attention in the realm of spintronic devices due to advantages such as ultrafast dynamics and a suppressed skyrmion Hall effect. Thus, understanding the behavior of nontrivial spin textures in ferrimagnets is crucial; however, comprehensive reports on this topic remain limited. Here, the magnetic spin textures of ferrimagnetic Mn 2 − x Zn x Sb (x = 0.85) is explored as a function of temperature and applied magnetic field. The spin textures can be tuned to a variety of states, including stripes, skyrmion bags, and a skyrmion lattice. Chiral Néel-type magnetic structures are visualized using Lorentz transmission electron microscopy. Mn(I) ions are slightly shifted toward the Sb sites, which may be due to a strong electrostatic interaction between Mn and Sb ions. This local structural distortion breaks the inversion symmetry and introduces an effective Dzyaloshinkii–Moriya interaction. This work thus provides a pathway to use doping and heterogeneity in a ferrimagnet to control and generate chiral nontrivial spin textures.

Mn ion displacement↗
DOE OSTI2023

Formation enthalpies of Al–Mn–Pd and the structure of the i-AlMnPd quasicrystal

Abstract This paper reports formation enthalpies of phases in the Al–Mn–Pd ternary alloy system as calculated from first principles using electronic density functional theory. We consider all crystal structures as reported in the assessed phase diagrams of the ternary and its binary alloy subsystems (Al–Mn, Al–Pd, and Mn–Pd), as well as additional reported or hypothetical structures. Icosahedral and decagonal quasicrystalline approximants are among the structures that we predict to be stable, or nearly so. Our results suggest the need for careful experimental reexamination of phase stability in each of the alloy systems, in tandem with further efforts to refine crystallographic and ab-initio structures.

17 WIND ENERGY↗
DOE OSTI2025

Current understanding of Oxidative Coupling of Methane (OCM) reaction over supported Mn-Na 2 WO 4 catalysts

This perspective reviews the current understanding of the Oxidative Coupling of Methane (OCM) reaction over the supported Mn-Na 2 WO 4 /SiO 2 catalyst, with a focus on recent insights gained from state-of-the-art in-situ and operando spectroscopic characterization and chemical probe experiments under controlled environments. The supported Mn-Na 2 WO 4 /SiO 2 catalyst exhibits dynamic structural changes during the OCM reaction, involving multiple reactive lattice and adsorbed oxygen species, each associated with different oxide phases. These oxygen species play distinct roles in various steps of the OCM mechanism. The catalytic active sites for activation of CH 4 are associated with isolated surface Na-WO x sites on the SiO 2 support and the role of surface MnO x sites on SiO 2 is to oxidatively dehydrogenate C 2 H 6 to C 2 H 4 . Furthermore, this paper provides a detailed discussion of these roles and also introduces new experimental data from Temporal Analysis of Products (TAP) studies to clarify the ongoing debate in the literature regarding the contributions of lattice versus adsorbed oxygen species in OCM reaction product formation. Additionally, recommendations are offered for optimizing the performance of supported Mn-Na 2 WO 4 /SiO 2 catalysts to enhance CH 4 activation and C 2 product selectivity.

03 - NATURAL GAS↗
DOE OSTI2021

Effects of Co doping on the structure and physicochemical properties of hausmannite (Mn 3 O 4 ) and its transformation during aging

Hausmannite is a common low-valence manganese oxide mineral with a distorted spinel structure in surficial sediments. Although natural Mn oxides often contain various transition metal (TM) impurities, few studies have addressed the substitution mechanisms of TMs, such as cobalt (Co), with hausmannite and induced changes in the mineral physicochemical properties. In this study, Co-doped hausmannites with final Co/Mn molar ratios of 0.05 and 0.11 were synthesized and characterized by wet chemical analysis, powder X-ray diffraction (XRD), Fourier transformed infrared spectra (FTIR), high resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure spectroscopy (XAFS). Co-doped samples have larger crystallite sizes and smaller specific surface areas than those of the hausmannite without Co. The Co cations exist in a mixed-valence of +3 and + 2. Powder XRD and acid dissolution experiments indicate that Co incorporates into the mineral structures, and increases the mineral structural stability. Co K-edge extended X-ray adsorption fine structure (EXAFS) analysis demonstrates that Co likely substitutes for lattice Mn(III). After aging at room temperature for three years, 14.1 ± 1.9% of pure hausmannite is transformed to manganite while only 2.6 ± 0.7% of manganite appears in the aged Co-doped sample with an initial Co/Mn molar ratio of 0.10. Finally, these results provide new insights into the incorporation mechanisms of TMs into low valence Mn oxides, and the stability of these minerals in natural environments.

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

Building interface bonding and shield for stable Li-rich Mn-based oxide cathode

Implementation of Li-rich Mn-based oxide cathode with high-energy-density has been restrained by capacity/voltage degradation that results from irreversible lattice oxygen loss and structure rearrangements. To resolve these challenges, in this work, Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 encapsulated by amorphous Co x B (CB-LRM) is rationally designed via autocatalytic plating for highly reversible cationic/anionic hybrid cathode material. Band coherency is ingeniously evoked by interface-reconstruction between bulk structure and amorphous coating layer, which lower the energy of O $2p$ states. Furthermore, this is associated with strengthened orbital hybridization of O $2p$-Mn $3d$ and increased formation energy of oxygen vacancy, which mitigates the lattice oxygen loss considerably. Additionally, interface shielding effects that protect electrode against electrolyte corrosion and the reduction of surface oxygen are also present with fully coverage of amorphous Co x B coating layer. As a result, the as-designed CBLRM cathode exhibits excellent cycle stability after 100 loops with only 0.154% per cycle capacity fade and improved voltage degradation. Given this, this work provides a potential avenue for rational design of lattice oxygen-based electrode materials with high-energy-density.

25 ENERGY STORAGE↗
DOE OSTI2020

Onset of magma ocean solidification on Mars inferred from Mn-Cr chronometry

The mantle of Mars probably differentiated through the crystallization of a magma ocean during the first tens of million years (Ma) of Solar System evolution. However, the exact timescale of large-scale silicate differentiation of the martian mantle is debated, and in particular, it remains unclear when differentiation commenced. In this paper, we applied the short-lived 53 Mn- 53 Cr system to martian meteorites in order to date the onset of large-scale mantle differentiation on Mars. The new Cr isotope data demonstrate that martian meteorites exhibit no resolvable radiogenic 53 Cr variations, and instead have a uniform +20.2±1.2 (95% conf.) parts-per-million excess in 53 Cr/ 52 Cr relative to the terrestrial mantle. The investigated groups of martian meteorites are lithologically varied and derive from diverse mantle sources that probably had variable Mn/Cr. Hence, the lack of 53 Cr variability among martian meteorites demonstrates that silicate differentiation on Mars occurred after the extinction of 53 Mn. Provided that the sources of the martian meteorites have Mn/Cr variations that are typical of the terrestrial planets, this result implies that the onset of large-scale silicate differentiation must have occurred later than 20±5 Ma after Solar System formation. The onset of silicate differentiation on Mars inferred here is significantly later than time estimates for segregation of the martian core which conservatively occurred within <10 Ma after Solar System formation. Thus, the new Mn-Cr data imply that there was a small, but resolvable, time gap of at least 5 Ma between core formation and magma ocean solidification on Mars. If the age of core segregation is taken at face value, our results imply that the martian magma ocean remained mostly molten over several Ma. This inferred longevity of the magma ocean is inconsistent with thermal models predicting rapid (<1 Ma) solidification of the martian magma ocean. Although there is currently no unique solution to this conundrum, our results can potentially be explained by a protracted history of impact bombardment that delayed differentiation in a shallow magma ocean on Mars, or perhaps more readily, by the presence of an early and dense atmosphere that acted as an insulator and prevented the magma ocean from cooling quickly.

58 GEOSCIENCES↗
DOE OSTI2020

Quasicrystalline phase and crystalline approximant in Ni–Mn–In Heusler alloy system

Intermetallic compounds and micro-structures in Ni–Mn–In alloy system were investigated with transmission electron microscopy, selected-area and nano-beam electron diffraction, and energy-dispersive x-ray spectroscopy. Together with two types of Heusler phases, a decagonal quasicrystalline phase and a structurally related crystallite were found in the Ni–Mn–In system. As is well-known, most of the decagonal quasicrystals are aluminum-based intermetallic phases. It is interesting to investigate the aluminum-free decagonal quasicrystalline phase as a new member of the quasicrystal family. Structural characterization was carried out on the decagonal quasicrystalline phase and the crystalline approximant in the Ni–Mn–In alloy system.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Excitation function of 54 Fe(p, α ) 51 Mn from 9.5 MeV to 18 MeV

Excitation function of the 54 Fe(p,α) 51 Mn reaction was measured from 9.5 to 18 MeV $E_{0,p^+}$ by activating a foil stack of 54 Fe electrodeposited on copper substrates. Residual radionuclides were quantified by HPGe gamma ray spectrometry. Both 51 Mn ($t_{1/2}$ = 46.2 min, $\langle E_{β^+}\rangle$=963.7keV, $I_{β^+}$ = 97%; $E_γ$ = 749.1keV, $I_γ$ = 0.265%) and its radioactive daughter, 51 Cr ($t_{1/2}$ = 27.704d, $E_γ$ = 320.1 keV, $I_γ$ = 9.91%), were used to indirectly quantify formation of 51 Mn. Results agree within uncertainty to the only other measurement in literature and predictions of default TALYS theoretical code. Final relative uncertainties are within ±12%.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Atomic Structural Features of Stacking Faults and Domain Connections in the Li- and Mn-Rich Cathode

Li- and Mn-rich layered oxides (LMRs), a class of earth-abundant materials for rechargeable Li-ion battery cathodes, crystallize into layered structures of two different symmetries: C2/m represented by Li 2 MnO 3 and R$\overline{3}$m represented by LiMn 0.5 Ni 0.5 O 2 . Fundamental questions about how the C2/m and R$\overline{3}$m domains spatially correlate within the same oxide grain and how the C2/m stacking faults arrange themselves when this happens still remain. Here, by using integrated differential phase contrast imaging in scanning transmission electron microscopy (STEM-iDPC), we probe the structural and compositional details of a prototypical, cobalt-free LMR material, 0.3Li 2 MnO 3 •0.7LiMn 0.5 Ni 0.5 O 2 (Li 1.13 Mn 0.57 Ni 0.3 O 2 ). The connection between the C2/m and R$\overline{3}$m domains is found to be abrupt, facilitated by the small lattice mismatch between the two structures. Stacking faults in the C2/m domains feature atomic plane shifting that accommodates stacking sequence changes, which explains why the stacking faults form in a random manner. Furthermore, a local disordering mechanism was identified to correlate with the C2/m stacking faults. Chemically, it is found that Ni coexists with Mn at the transition metal sites within the nominal Li 2 MnO 3 domain. As a result, this study demonstrates that STEM-iDPC is a very useful tool for capturing all the elements in a single image, revealing atomic details on domain connections and stacking faults in the LMRs.

Li-rich and Mn-rich oxides↗
DOE OSTI2023

Rapid solidified ductile Cu-Al-Mn ribbon and its elastocaloric potential

Abstract Cu-Al-Mn alloys display martensitic transformation over a wide range of temperatures. In addition to low cost, this alloy is known for its low transformation stress with reasonable latent heat favoring elastocaloric applications. However, the ductility of Cu-Al-Mn can be limited owing to ordering and intergranular fracture. Through rapid solidification by melt spinning, we show that Cu-Al-Mn ribbon can be made highly ductile (greater than 8% tensile strain in the as-spun state and 10% tensile strain after heat treatment). The ductility of the melt-spun ribbon is related to the suppression of L2 1 ordering that is characterized through magnetic property measurement. Heat treatment of the ribbon promotes bamboo grain formation, and the latent heat is increased to 6.4 J g −1 . Under tensile conditions, we show that the ribbon exhibited about 4 °C temperature change (4.4 °C on heating and 4.2 °C on cooling from 6.3% strain).

36 MATERIALS SCIENCE↗
DOE OSTI2022

Tailoring Disordered/Ordered Phases to Revisit the Degradation Mechanism of High‐Voltage LiNi 0.5 Mn 1.5 O 4 Spinel Cathode Materials

Abstract In the spinel oxide cathode family, LiNi 0.5 Mn 1.5 O 4 (LNMO) shows a high operating voltage (≈4.7 V vs Li/Li + ) and excellent Li‐ion mobility with stable 3D conducting channels. Ni/Mn cation disordered and ordered phases usually coexist in LNMO materials, and they have distinct structural and electrochemical properties, resulting in different battery performances for LNMO materials with different phase compositions. Identifying the correlation between phase compositions and electrochemical properties is of significance to the improvement of battery performance and understanding of degradation mechanisms. Herein, the disordered/ordered phase compositions in LNMO materials are tailored by post‐annealing strategies and their impacts on electrochemical performance and degradation mechanisms from the surface to the bulk are systematically investigated. The ordered phase increases rapidly as Mn 3+ is oxidized to Mn 4+ through a post‐annealing process. LNMO with an intermediate fraction of disordered and ordered phases gives rise to improved cycling stability. This article further reports that a high ordered phase fraction can preferentially protect Ni from dissolution during cycling. However, these results suggest that the transition metal dissolution and surface structural change of LNMO do not exhibit a direct correlation with cycling stability. These results indicate the capacity fading mainly correlates with the bulk structural distortion, leading to decreased Li‐ion kinetics.

36 MATERIALS SCIENCE↗