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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Mn5VO12 by Materials Project

VMn2O6(MnO2)3 is trigonal omega-derived structured and crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one MnO2 sheet oriented in the (0, 0, 1) direction and one VMn2O6 sheet oriented in the (0, 0, 1) direction. In the MnO2 sheet, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There is two shorter (1.94 Å) and four longer (1.95 Å) Mn–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Mn4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Mn4+ atoms. In the VMn2O6 sheet, V4+ is bonded to six O2- atoms to form VO6 octahedra that share edges with six equivalent MnO6 octahedra. There is two shorter (1.91 Å) and four longer (1.98 Å) V–O bond length. Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share edges with three equivalent VO6 octahedra and edges with three equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–1.97 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one V4+ and two equivalent Mn4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one V4+ and two equivalent Mn4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaMn5O11 by Materials Project

BaO(MnO2)5 crystallizes in the monoclinic Cm space group. The structure is three-dimensional and consists of two BaO ribbons oriented in the (0, 1, 0) direction and one MnO2 framework. In each BaO ribbon, Ba2+ is bonded in a 2-coordinate geometry to two equivalent O2- atoms. Both Ba–O bond lengths are 2.40 Å. O2- is bonded in a distorted L-shaped geometry to two equivalent Ba2+ atoms. In the MnO2 framework, there are five inequivalent Mn4+ sites. In the first Mn4+ site, Mn4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Mn–O bond distances ranging from 1.92–2.02 Å. In the second Mn4+ site, Mn4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of Mn–O bond distances ranging from 1.95–2.16 Å. In the third Mn4+ site, Mn4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Mn–O bond distances ranging from 1.95–2.02 Å. In the fourth Mn4+ site, Mn4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are a spread of Mn–O bond distances ranging from 1.91–1.99 Å. In the fifth Mn4+ site, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.89–2.02 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to three Mn4+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Mn4+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three Mn4+ atoms. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to three Mn4+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three Mn4+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Mn4+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to three Mn4+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Mn4+ atoms. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Mn4+ atoms. In the tenth O2- site, O2- is bonded in a trigonal planar geometry to three Mn4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MnCO3 by Materials Project

MnCO3 crystallizes in the monoclinic C2/c space group. The structure is one-dimensional and consists of four formaldehyde molecules and two MnO2 ribbons oriented in the (0, 0, 1) direction. In each MnO2 ribbon, Mn2+ is bonded in a distorted square co-planar geometry to four equivalent O2- atoms. All Mn–O bond lengths are 1.91 Å. O2- is bonded in a water-like geometry to two equivalent Mn2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Non-destructive electrochemical diagnosis of failure mechanisms in aqueous zinc batteries

The early detection of secondary reactions that affect the life and performance of zinc manganese oxide batteries requires a shift from conventional time-consuming and often destructive procedures to rapid lifetime-predictive techniques. In this work, an electrochemical approach is employed to elucidate independent signatures for four common types of failure mechanisms in zinc manganese dioxide (Zn||MnO2) batteries—namely, the loss of zinc inventory, the loss of active material at the cathode, electrolyte depletion, and increased cell impedance. Our findings, specific to coin cell configurations, reveal that each induced failure mechanism can be distinctively modeled and identified based on responses from the rest voltage and columbic-efficiency data for prompt detection. For instance, electrolyte depletion response manifests a distinctive abrupt (>80 %) decrease in columbic efficiency (CE) and charge-rest voltage (Vc) while the discharge-rest voltage remained constant at ~1.3 V. Furthermore, electrolyte rejuvenation of the cell increased the CE to >95 % and restored Vc from ~0.3 to >1.7 V. Recovery experiments and reference performance tests demonstrated consistency between electrochemical descriptors and their associated failure mechanisms. Further, the outcomes of this work provide valuable insights and data models for some of the dominant failure mechanisms present in zinc manganese battery chemistries, which are beneficial to accelerated early-lifetime diagnosis and advancement of Zn batteries development.

25 ENERGY STORAGE↗
DOE OSTI2021

Changing chemistry of particulate manganese in the near- and far-field hydrothermal plumes from 15°S East Pacific Rise and its influence on metal scavenging

Dissolved Mn(II) in the hydrothermal plume is known to be microbially oxidized to form Mn(III/IV) oxides, and the Mn oxides scavenge other trace elements in seawater. In the GEOTRACES GP16 cruise, dissolved Mn (dMn) and particulate Mn (pMn) were found to be transported over 4000 km westwards from the Southern Eastern Pacific Rise. Previous studies in this plume showed different removal rates of dMn and pMn as well as pMn size distribution between the near-field (<80 km from the ridge axis) and far-field (>80 km) plumes. In order to understand Mn cycling in these plumes, spatial distribution, oxidation states, and mineral structures of Mn in small size fraction (SSF; 0.8–51 μm) and large size fraction (LSF; >51 μm) particles from the near-field and far-field plumes were examined using micro X-ray fluorescence spectrometry (μ-XRF), X-ray absorption near-edge structure spectroscopy (XANES), chemical species mapping, and extended X-ray absorption fine-structure spectroscopy (EXAFS). In the near-field plume, pMn in the SSF is dominated by oxidized Mn with Mn(III) fractions of ~30%. They are a mixture of δ-MnO 2 and triclinic birnessites that is known to be formed as a result of autocatalytic Mn(II) oxidation at the surface of freshly-formed δ-MnO2, suggesting that both microbial and autocatalytic Mn oxidation occur in the near-field plume. The LSF pMn in the near-field plume is also oxidized and often found in large aggregates several hundreds of μm in size. These aggregates settle out in the near-field and during transport, and are not found in the far-field plume. In the far-field plume where Mn oxides are not newly formed, pMn in the SSF is oxidized, but their Mn(III) fractions are smaller than in the near-field pMn. Unlike the SSF, the far-field plume LSF pMn is dominated by reduced Mn, implying very slow aggregation of pMn in the far-field plume. The different characteristics of pMn between the near-field and far-field plumes affect its scavenging of other trace elements. In the near-field plume, Co, Mo, 231 Pa are associated with pMn, but not in the far-field plume. 231 Pa is adsorbed to pFe rather than pMn in the far-field plume, and Pb is adsorbed to pFe in the entire plume. The result shows that freshly-formed Mn oxides in the near-field plume have higher scavenging capacity than the far-field plume pMn. Our findings suggest that the mineralogical age of Mn oxides may be an important parameter that controls the scavenging of many other trace elements and isotopes.

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

Nanoscale hydration in layered manganese oxides

Birnessite is a layered MnO2 mineral with a nanoscale interlayer region that accommodates layers of intercalated water. Variable distributions of Mn sites with oxidation states of II, III and IV are responsible for the high catalytic reactivity of birnessite in nature and as a valuable candidate for energy storage solutions. We here report water loading capabilities and the vibrational spectral signatures of two forms of birnessite of strongly contrasting particle size. Using X-ray diffraction we find that potassium-birnessite accommodates no more than one monolayer (1W) of water in its interlayer region. Molecular simulations show that this is an energetically favorable hydration state where interlayer potassium-water and direct water-birnessite interactions are greater than at other hydration levels. Simulations also suggest a stable 2W state but that is not achieved experimentally by contact with water vapor. Finally, this work provides a means to predict the distribution of adsorbed and interlayer water molecules using a recently developed composite model.

Cheng, Wei↗
DOE OSTI2021

Impact of Stabilizing Cations on Lithium Intercalation in Tunneled Manganese Oxide Cathodes

Stabilizing cations such as K + , Ba 2+ , and Ag + are known to provide charge neutrality and enhance structural stability in low-cost tunneled manganese dioxide (MnO 2 ) cathodes for Li ion batteries. However, a fundamental understanding of the role of these cations in the electrochemical performance of tunneled MnO 2 cathodes remains unclear, especially at low stabilizing cation concentrations. Here, we employ density functional theory (DFT + U) calculations to reveal the impact of stabilizing potassium cation (K + ) concentration on the structural stability, electronic properties, and kinetics of lithium transport in 2 x 2 tunneled manganese oxide (α-K y Mn 8 O 16 , at y = 0, 1, and 2) battery cathodes during lithium intercalation. Specifically, we provide insights into the effect of K + ions on several critical factors governing the electrochemical storage performance of tunneled MnO2 cathodes, including (a) energetically favorable Li+ host sites, (ii) Li + and electron transport capabilities, (iii) optimal intercalation pathways, crystal distortion, microstructural stability, and tunneled-to-layer phase transformation as a function of lithium content, and (iv) cell output voltage profile. Interestingly, we find that low K + concentrations (y ≤ 1) yield partially cation-deficient tunnels in the MnO 2 cathode. Such unique tunnel structures in the cathode enable (a) low kinetic barriers for Li transport, (b) excellent thermodynamic stability of the tunneled structure even at a high Li + loading (up to ~ 0.625 Li/Mn), and (c) good electronic conductivity facilitated by Jahn-Teller distortions; all of which are critical for achieving high capacity batteries with enhanced rate capability. Additionally, these results provide perspectives to design low-cost transition metal oxide cathodes for high-performance Li-ion batteries with excellent cycle life.

25 ENERGY STORAGE↗
DOE OSTI2020

Electrodeposited Zinc-based Films as Anodes for Aqueous Zinc Batteries

Zinc-based batteries have attracted extensive attention in recent years, due to high safety, high capacities, environmental friendliness, and low cost compared to lithium ion batteries. However, the zinc anode suffers primarily from dendrite formation as a mode of failure in the mildly acidic system. Herein, we report on electrochemically deposited zinc (ED Zn) and copper-zinc (brass) alloy anodes, which are critically compared with a standard commercial zinc foil. The film electrodes are of commercially relevant thicknesses (21 and 25µM). The electrodeposited zinc-based anodes exhibit low electrode polarization (~0.025V) and stable cycling performance in 50 cycle consecutive experiments from 0.26-10 mA cm-2 compared to commercial Zn foil. Coulombic efficiencies at 1 mA cm-2 were over 98% for the electrodeposited zinc-based materials and were maintained for over 100 cycles. Furthermore, full cells with an electrodeposited Zn/brass anode, EMD MnO2 cathode, in 1M ZnSO4 + 0.1M MnSO4 delivered capacities of 96.3, and 163 mAh g-1, respectively, at a 100 mA g-1 compared to 92.1 mAh g-1 for commercial Zn. The zinc-based anodes also show better rate capability, delivering full cell capacities of 35.9 and 47.5 mAh g-1 at high current of up to 3 A g-1. Lastly, the electrodeposited zinc-based anodes show enhanced capacity for up to 100 cycles at 100 mA g-1, making them viable anodes for commercial use.

Fayette, Matthew R.↗