and Peter Zavalij

Bio: and Peter Zavalij is an academic researcher from Binghamton University. The author has contributed to research in topics: Hydrothermal circulation & Lamellar phase. The author has an hindex of 3, co-authored 3 publications receiving 316 citations.

Hydrothermal Synthesis and Characterization of KxMnO2·yH2O

Abstract: We report here the direct synthesis of a hexagonal form of manganese dioxide using mild hydrothermal methods. The reaction of potassium or sodium permanganate in water at 170 °C leads directly to potassium or sodium manganese dioxide, Alk≈0.25MnO2·0.6H2O, with a R3m rhombohedral structure like Lix(H2O)TiS2 and a 7 A repeat distance indicative of a monolayer of water between the manganese dioxide layers. This manganese oxide reacts readily and reversibly with lithium ions.

Novel Tungsten, Molybdenum, and Vanadium Oxides Containing Surfactant Ions

Abstract: Hydrothermal reaction of tungstic acid, molybdic acid, and vanadium pentoxide with the surfactant template dodecyltrimethylammonium bromide (DTABr) yielded one compound with a Keggin type structure, [C12H25N(CH3)3]6(H2W12O40)·xH2O, and two new layered compounds, [C12H25N(CH3)3]0.5(MoO3.25) and [C12H25N(CH3)3]2/3V2O5.33·H2O. The tungsten salt produced needlelike crystals of a hexagonal shape while the molybdenum and vanadium salts formed layered structures. FTIR analysis of the tungsten salt was consistent with materials containing Keggin anions. The X-ray powder diffraction data of this material were indexed to a monoclinic cell with a = 50.56(4) A, b = 54.41(4) A, c = 13.12(1) A, and β = 99.21°. The observed reflections are consistent with space group C2/m. Diffraction data obtained from the molybdenum salt showed a between layer d spacing of ca. 22 A. The vanadium salt was indexed to a triclinic cell with a = 9.813(3) A, b = 11.512(3) A, c = 21.725(5) A, α = 95.30(1)°, β = 93.82(6)°, and γ = 101.12(8)°,...

Evidence for Decavanadate Clusters in the Lamellar Surfactant Ion Phase

Abstract: Single-crystal X-ray analysis shows the lamellar phase of the vanadium oxide surfactant contains discrete decavanadate clusters and not a continuous vanadium oxide sheet. The clusters are hydrogen bonded together through water molecules forming layers. Between these layers long-chain surfactant chains of dodecyltrimethylammonium lay in parallel with their headgroups stacked in opposite directions. Water and small alcohols can be reversibly inserted into this structure expanding the interlayer spacing.

Lithium Batteries and Cathode Materials

Abstract: In the previous paper Ralph Brodd and Martin Winter described the different kinds of batteries and fuel cells. In this paper I will describe lithium batteries in more detail, building an overall foundation for the papers that follow which describe specific components in some depth and usually with an emphasis on the materials behavior. The lithium battery industry is undergoing rapid expansion, now representing the largest segment of the portable battery industry and dominating the computer, cell phone, and camera power source industry. However, the present secondary batteries use expensive components, which are not in sufficient supply to allow the industry to grow at the same rate in the next decade. Moreover, the safety of the system is questionable for the large-scale batteries needed for hybrid electric vehicles (HEV). Another battery need is for a high-power system that can be used for power tools, where only the environmentally hazardous Ni/ Cd battery presently meets the requirements. A battery is a transducer that converts chemical energy into electrical energy and vice versa. It contains an anode, a cathode, and an electrolyte. The anode, in the case of a lithium battery, is the source of lithium ions. The cathode is the sink for the lithium ions and is chosen to optimize a number of parameters, discussed below. The electrolyte provides for the separation of ionic transport and electronic transport, and in a perfect battery the lithium ion transport number will be unity in the electrolyte. The cell potential is determined by the difference between the chemical potential of the lithium in the anode and cathode, ∆G ) -EF. As noted above, the lithium ions flow through the electrolyte whereas the electrons generated from the reaction, Li ) Li+ + e-, go through the external circuit to do work. Thus, the electrode system must allow for the flow of both lithium ions and electrons. That is, it must be both a good ionic conductor and an electronic conductor. As discussed below, many electrochemically active materials are not good electronic conductors, so it is necessary to add an electronically conductive material such as carbon * To whom correspondence should be addressed. Phone and fax: (607) 777-4623. E-mail: stanwhit@binghamton.edu. 4271 Chem. Rev. 2004, 104, 4271−4301

Chemical strategies to design textured materials: from microporous and mesoporous oxides to nanonetworks and hierarchical structures.

Abstract: 3.

Advances in manganese-oxide ‘composite’ electrodes for lithium-ion batteries

Abstract: Recent advances to develop manganese-rich electrodes derived from ‘composite’ structures in which a Li2MnO3 (layered) component is structurally integrated with either a layered LiMO2 component or a spinel LiM2O4 component, in which M is predominantly Mn and Ni, are reviewed. The electrodes, which can be represented in two-component notation as xLi2MnO3·(1 − x)LiMO2 and xLi2MnO3·(1 − x)LiM2O4, are activated by lithia (Li2O) and/or lithium removal from the Li2MnO3, LiMO2 and LiM2O4 components. The electrodes provide an initial capacity >250 mAh g−1 when discharged between 5 and 2.0 V vs. Li0 and a rechargeable capacity up to 250 mAh g−1 over the same potential window. Electrochemical charge and discharge reactions are followed on compositional phase diagrams. The data bode well for the development and exploitation of high capacity electrodes for the next generation of lithium-ion batteries.