The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Michael A. Hayward - One of the best experts on this subject based on the ideXlab platform.

  • rhodium containing Oxide hydrides covalently stabilized mixed anion solids
    Chemical Communications, 2019
    Co-Authors: Lun Jin, Michael A. Hayward
    Abstract:

    The first rhodium-containing Oxide-hydride phases, LaSrCo0.5Rh0.5O3H and La0.5Sr1.5Mn0.5Rh0.5O3H, have been prepared via topochemical anion exchange. This clearly demonstrates the ability of rhodium, a late 4d Transition Metal, to kinetically stabilize Oxide-hydride lattices, reinforcing the paradigm of covalent stabilization of Transition-Metal Oxide-hydride phases.

  • sr3co2o4 33h0 84 an extended Transition Metal Oxide hydride
    ChemInform, 2011
    Co-Authors: Rebecca M. Helps, Nicholas H Rees, Michael A. Hayward
    Abstract:

    The title compound is prepared by reaction of Sr3Co2O5.80 (obtained from stoichiometric mixtures of SrCO3 and Co3O4 at 1100 °C for 40 h) with CaH2 (Ar, 24 h at 240 °C, 48 h at 250 °C, and 24 h at 255 °C) and its structure is determined by neutron powder diffraction.

  • Sr3Co2O4.33H0.84: An extended Transition Metal Oxide-hydride
    Inorganic Chemistry, 2010
    Co-Authors: Rebecca M. Helps, Nicholas H Rees, Michael A. Hayward
    Abstract:

    Reaction of the n = 2 Ruddlesden−Popper Oxide Sr3Co2O5.80 with CaH2 yields an extended Oxide-hydride phase: Sr3Co2O4.33H0.84. Neutron powder diffraction data reveal the material adopts a body-centered orthorhombic structure (Immm: a = 3.7551(5) Å, b = 3.7048(4) Å, c = 21.480(3) Å) in which the hydride ions are accommodated within disordered CoO1.16H0.46 layers. Low temperature neutron powder diffraction data show no evidence for long-range magnetic order, suggesting the chemical disorder in the anion lattice of the material leads to magnetic frustration.

  • electronic structure magnetic ordering and formation pathway of the Transition Metal Oxide hydride lasrcoo 3 h 0 7
    Journal of the American Chemical Society, 2005
    Co-Authors: Craig A Bridges, Michael A. Hayward, G R Darling, Matthew J Rosseinsky
    Abstract:

    The role of the hydride anion in controlling the electronic properties of the Transition Metal Oxide hydride LaSrCoO(3)H(0.7) is investigated theoretically by full potential DFT band structure calculation and experimentally by determination of the Neel temperature for three-dimensional magnetic ordering. The mechanism by which hydrogen is introduced into the solid is addressed by in situ X-ray diffraction studies of the formation of the Oxide hydride, which reveal both a relationship between the microscopic growth of the observed Oxide hydride order and the anisotropic broadening of the diffraction profile, and the existence of a range of intermediate compositions.

  • the hydride anion in an extended Transition Metal Oxide array lasrcoo3h0 7
    Science, 2002
    Co-Authors: Michael A. Hayward, Edmund J Cussen, John B Claridge, M Bieringer, Matthew J Rosseinsky, Christopher J Kiely, Stephen J Blundell, I M Marshall, F L Pratt
    Abstract:

    We present the synthesis and structural characterization of a Transition Metal Oxide hydride, LaSrCoO3H0.7, which adopts an unprecedented structure in which Oxide chains are bridged by hydride anions to form a two-dimensional extended network. The Metal centers are strongly coupled by their bonding with both Oxide and hydride ligands to produce magnetic ordering at temperatures up to at least 350 kelvin. The synthetic route is sufficiently general to allow the prediction of a new class of Transition Metal–containing electronic and magnetic materials.

Gerbrand Ceder - One of the best experts on this subject based on the ideXlab platform.

  • stoichiometric layered potassium Transition Metal Oxide for rechargeable potassium batteries
    Chemistry of Materials, 2018
    Co-Authors: Haegyeom Kim, Gerbrand Ceder, Donghwa Seo, Alexander Urban, Jinhyuk Lee, Deokhwang Kwon, Tan Shi, Joseph K Papp, Bryan D Mccloskey
    Abstract:

    K-ion batteries are promising alternative energy storage systems for large-scale applications because of the globally abundant K reserves. K-ion batteries benefit from the lower standard redox potential of K/K+ than that of Na/Na+ and even Li/Li+, which can translate into a higher working voltage. Stable KC8 can also be formed via K intercalation into a graphite anode, which contrasts with the thermodynamically unfavorable Na intercalation into graphite, making graphite a readily available anode for K-ion battery technology. However, to construct practical rocking-chair K-ion batteries, an appropriate cathode material that can accommodate reversible K release and storage is still needed. We show that stoichiometric KCrO2 with a layered O3-type structure can function as a cathode for K-ion batteries and demonstrate a practical rocking-chair K-ion battery. In situ X-ray diffraction and electrochemical titration demonstrate that KxCrO2 is stable for a wide K content, allowing for topotactic K extraction and ...

  • fluorination of lithium excess Transition Metal Oxide cathode materials
    Advanced Energy Materials, 2018
    Co-Authors: William D Richards, Stephen Dacek, Daniil A Kitchaev, Gerbrand Ceder
    Abstract:

    Fluorination of Li-ion cathode materials is of significant interest as it is claimed to lead to significant improvements in long-term reversible capacity. However, the mechanism by which LiF incorporates and improves performance remains uncertain. Indeed, recent evidence suggests that fluorine is often present as a coating layer rather than incorporated into the bulk of the material. In this work, first-principles calculations are used to investigate the thermodynamics of fluorination in Transition Metal Oxide cathodes to determine the conditions under which bulk fluorination is possible. It is found that unlike classic well-ordered cathodes, which cannot incorporate fluorine, disordered rock salt-structured materials achieve significant fluorination levels due to the presence of locally Metal-poor, lithium-rich environments that are highly preferred for fluorine. As well as explaining the fluorination process in known materials, this finding is encouraging for the development of new disordered rock salt lithium-excess Transition Metal Oxides, a promising new class of Li-ion battery cathode materials that offer superior practical capacity to traditional layered Oxides. In particular, it is found that bulk fluorination may serve as an alternative source of Li-excess in these compounds that can replace the conventional substitution of a heavy redox-inactive element on the Transition Metal sublattice.

Khalil Amine - One of the best experts on this subject based on the ideXlab platform.

  • holey two dimensional Transition Metal Oxide nanosheets for efficient energy storage
    Nature Communications, 2017
    Co-Authors: Lele Peng, Pan Xiong, Yifei Yuan, Yue Zhu, Dahong Chen, Xiangyi Luo, Khalil Amine
    Abstract:

    Transition Metal Oxide nanomaterials are promising electrodes for alkali-ion batteries owing to their distinct reaction mechanism, abundant active sites and shortened ion diffusion distance. However, detailed conversion reaction processes in terms of the oxidation state evolution and chemical/mechanical stability of the electrodes are still poorly understood. Herein we explore a general synthetic strategy for versatile synthesis of various holey Transition Metal Oxide nanosheets with adjustable hole sizes that enable greatly enhanced alkali-ion storage properties. We employ in-situ transmission electron microscopy and operando X-ray absorption structures to study the mechanical properties, morphology evolution and oxidation state changes during electrochemical processes. We find that these holey Oxide nanosheets exhibit strong mechanical stability inherited from graphene Oxide, displaying minimal structural changes during lithiation/delithiation processes. These holey Oxide nanosheets represent a promising material platform for in-situ probing the electrochemical processes, and could open up opportunities in many energy storage and conversion systems.

  • holey two dimensional Transition Metal Oxide nanosheets for efficient energy storage
    Nature Communications, 2017
    Co-Authors: Lele Peng, Pan Xiong, Yifei Yuan, Dahong Chen, Khalil Amine, Jun Lu, Guihua Yu
    Abstract:

    Transition Metal Oxide nanomaterials are promising electrodes for alkali-ion batteries owing to their distinct reaction mechanism, abundant active sites and shortened ion diffusion distance. However, detailed conversion reaction processes in terms of the oxidation state evolution and chemical/mechanical stability of the electrodes are still poorly understood. Herein we explore a general synthetic strategy for versatile synthesis of various holey Transition Metal Oxide nanosheets with adjustable hole sizes that enable greatly enhanced alkali-ion storage properties. We employ in-situ transmission electron microscopy and operando X-ray absorption structures to study the mechanical properties, morphology evolution and oxidation state changes during electrochemical processes. We find that these holey Oxide nanosheets exhibit strong mechanical stability inherited from graphene Oxide, displaying minimal structural changes during lithiation/delithiation processes. These holey Oxide nanosheets represent a promising material platform for in-situ probing the electrochemical processes, and could open up opportunities in many energy storage and conversion systems. As alkali-ion battery anodes, Metal Oxide nanomaterials suffer from severe structural degradation after charging/discharging cycling. Here the authors develop two-dimensional holey nanosheet anodes which display minimal structural changes during electrochemical operation.

  • atomic resolution visualization of distinctive chemical mixing behavior of ni co and mn with li in layered lithium Transition Metal Oxide cathode materials
    Chemistry of Materials, 2015
    Co-Authors: Pengfei Yan, Jianming Zheng, Yi Wei, Jiaxin Zheng, Zhiguo Wang, Saravanan Kuppan, Langli Luo, Danny J Edwards, Matthew J Olszta, Khalil Amine
    Abstract:

    Capacity and voltage fading of layered structured cathode based on lithium Transition-Metal Oxide is closely related to the lattice position and migration behavior of the Transition-Metal ions. However, it is scarcely clear about the behavior of each of these Transition-Metal ions in this category of cathode material. We report direct atomic resolution visualization of interatomic layer mixing of Transition Metals (Ni, Co, Mn) and lithium ions in layered structured Oxide cathodes for lithium-ion batteries. Using chemical imaging with an aberration-corrected scanning transmission electron microscope (STEM) and density function theory calculations, we discovered that, in the layered cathodes, Mn and Co tend to reside almost exclusively at the lattice site of Transition-Metal (TM) layer in the structure or little interlayer mixing with Li. In contrast, Ni shows a high degree of interlayer mixing with Li. The fraction of Ni ions resides in the Li layer followed by a near linear dependence on total Ni concentr...

Peter C Burns - One of the best experts on this subject based on the ideXlab platform.

  • hybrid uranium Transition Metal Oxide cage clusters
    ChemInform, 2015
    Co-Authors: Jie Ling, Franklin Hobbs, Steven Prendergast, Pius O Adelani, Jeanmarie Babo, Jie Qiu, Zhehui Weng, Peter C Burns
    Abstract:

    The cage clusters (IV) and (VI)—(X) are self-assembled in aqueous solution under ambient conditions and subsequently crystallized.

  • hybrid uranium Transition Metal Oxide cage clusters
    Inorganic Chemistry, 2014
    Co-Authors: Jie Ling, Franklin Hobbs, Steven Prendergast, Pius O Adelani, Jeanmarie Babo, Jie Qiu, Zhehui Weng, Peter C Burns
    Abstract:

    Transition-Metal based polyoxoMetalate clusters have been known for decades, whereas those built from uranyl perOxide polyhedra have more recently emerged as a family of complex clusters. Here we report the synthesis and structures of six nanoscale uranyl perOxide cage clusters that contain either tungstate or molybdate polyhedra as part of the cage, as well as phosphate tetrahedra. These Transition-Metal–uranium hybrid clusters exhibit unique polyhedral connectivities and topologies that include 6-, 7-, 8-, 10-, and 12-membered rings of uranyl polyhedra and uranyl ions coordinated by bidentate perOxide in both trans and cis configurations. The Transition-Metal polyhedra appear to stabilize unusual units built of uranyl polyhedra, rather than templating their formation.

Yury Gogotsi - One of the best experts on this subject based on the ideXlab platform.

  • self assembly of Transition Metal Oxide nanostructures on mxene nanosheets for fast and stable lithium storage
    Advanced Materials, 2018
    Co-Authors: Yitao Liu, Babak Anasori, Yury Gogotsi, Qizhen Zhu, Peng Zhang, Ning Sun, Huan Liu
    Abstract:

    Recently, a new class of 2D materials, i.e., Transition Metal carbides, nitrides, and carbonitrides known as MXenes, is unveiled with more than 20 types reported one after another. Since they are flexible and conductive, MXenes are expected to compete with graphene and other 2D materials in many applications. Here, a general route is reported to simple self-assembly of Transition Metal Oxide (TMO) nanostructures, including TiO2 nanorods and SnO2 nanowires, on MXene (Ti3 C2 ) nanosheets through van der Waals interactions. The MXene nanosheets, acting as the underlying substrate, not only enable reversible electron and ion transport at the interface but also prevent the TMO nanostructures from aggregation during lithiation/delithiation. The TMO nanostructures, in turn, serve as the spacer to prevent the MXene nanosheets from restacking, thus preserving the active areas from being lost. More importantly, they can contribute extraordinary electrochemical properties, offering short lithium diffusion pathways and additional active sites. The resulting TiO2 /MXene and SnO2 /MXene heterostructures exhibit superior high-rate performance, making them promising high-power and high-energy anode materials for lithium-ion batteries.