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

http://www.chemie.uni-regensburg.de/Anorganische_Chemie/Vortrag/StudentenWS06-07/Vortrag_Amereller.pdf

Lithium Batteries and Cathode Materials

It is possible to say that zeolites are the most widely used catalysts in industry They are crystalline microporous materials which have become extremely successful as catalysts for oil refining, petrochemistry, and organic synthesis in the production of fine and speciality chemicals, particularly when dealing with molecules having kinetic diameters below 10 A The reason for their success in catalysis is related to the following specific features of these materials:1 (1) They have very high surface area and adsorption capacity (2) The adsorption properties of the zeolites can be controlled, and they can be varied from hydrophobic to hydrophilic type materials (3) Active sites, such as acid sites for instance, can be generated in the framework and their strength and concentration can be tailored for a particular application (4) The sizes of their channels and cavities are in the range typical for many molecules of interest (5-12 A), and the strong electric fields2 existing in those micropores together with an electronic confinement of the guest molecules3 are responsible for a preactivation of the reactants (5) Their intricate channel structure allows the zeolites to present different types of shape selectivity, ie, product, reactant, and transition state, which can be used to direct a given catalytic reaction toward the desired product avoiding undesired side reactions (6) All of these properties of zeolites, which are of paramount importance in catalysis and make them attractive choices for the types of processes listed above, are ultimately dependent on the thermal and hydrothermal stability of these materials In the case of zeolites, they can be activated to produce very stable materials not just resistant to heat and steam but also to chemical attacks Avelino Corma Canos was born in Moncofar, Spain, in 1951 He studied chemistry at the Universidad de Valencia (1967−1973) and received his PhD at the Universidad Complutense de Madrid in 1976 He became director of the Instituto de Tecnologia Quimica (UPV-CSIC) at the Universidad Politecnica de Valencia in 1990 His current research field is zeolites as catalysts, covering aspects of synthesis, characterization and reactivity in acid−base and redox catalysis A Corma has written about 250 articles on these subjects in international journals, three books, and a number of reviews and book chapters He is a member of the Editorial Board of Zeolites, Catalysis Review Science and Engineering, Catalysis Letters, Applied Catalysis, Journal of Molecular Catalysis, Research Trends, CaTTech, and Journal of the Chemical Society, Chemical Communications A Corma is coauthor of 20 patents, five of them being for commercial applications He has been awarded with the Dupont Award on new materials (1995), and the Spanish National Award “Leonardo Torres Quevedo” on Technology Research (1996) 2373 Chem Rev 1997, 97, 2373−2419

From Microporous to Mesoporous Molecular-Sieve Materials and Their Use in Catalysis

IN two previous notes1, Prof. Max Born and I have shown that one can obtain a theory of superconductivity by taking account of the fact that the interaction of the electrons with the ionic lattice is appreciable only near the boundaries of Brillouin zones, and particularly strong near the corners of these. This leads to the criterion that the metal should be superconductive if a set of corners of a Brillouin zone is lying very near the Fermi surface, considered as a sphere, which limits the region in the momentum space completely filled with electrons.

On the theory of superconductivity

Polyoxometalates (POMs) are a subset of metal oxides that represent a diverse range of molecular clusters with an almost unmatched range of physical properties and the ability to form dynamic structures that can range in size from the nano- to the micrometer scale Herein we present the very latest developments from synthesis to structure and function of POMs We discuss the possibilities of creating highly sophisticated functional hierarchical systems with multiple, interdependent, functionalities along with a critical analysis that allows the non-specialist to learn the salient features We propose and present a "periodic table of polyoxometalate building blocks" We also highlight some of the current issues and challenges that need to be addressed to work towards the design of functional systems based upon POM building blocks and look ahead to possible emerging application areas

Polyoxometalates: Building Blocks for Functional Nanoscale Systems

https://web.iitd.ac.in/~arunku/files/CEL311_Y13/Adsorption%20Theory%20to%20practice_Dabrowski.pdf

Adsorption — from theory to practice

The electronic properties of crystals with a layered structure can be radically altered by the intercalation, between the layers, of guest species that act as electron donors or acceptors. Such studies have been performed extensively on graphite, transition-metal dichalcogenides and oxide bronzes1. Interest in redox intercalation reactions2 has increased recently because the high-transition-temperature (high-Tc) superconductors based on copper oxide also have layered structures, the superconductivity occurring within two-dimensional CuO2 planes separated by charge-reservoir oxide layers3. Similarly, in metal-doped fullerenes, which show relatively high transition temperatures, the electron donor atoms sit in the interstitial sites between adjacent fullerene balls4. In a previous study5, we described a layered nitride, β-ZrNCl, consisting of Zr–N double layers sandwiched between two close-packed chlorine layers. On lithium intercalation, the crystal changed from a semiconductor to a metal, and became a superconductor at 13 K. Here we report the properties of the isostructural compound β-HfNCl. After electron-doping the crystal by lithium intercalation, we observe superconductivity with a Tc of up to 25.5 K. This transition temperature is higher than that observed in any intermetallic compound, and suggests that layered nitride structures may offer transition temperatures comparable to those observed in layered copper oxide structures.

Superconductivity at 25.5 K in electron-doped layered hafnium nitride

A new silicon clathrate compound containing barium, (Na,Ba) ${}_{x}$S${\mathrm{i}}_{46}$, becomes a type-II superconductor with a critical temperature $({T}_{\mathrm{c}})$ of about 4 K. In the compound, the silicon atoms are bonded tetrahedrally with about the same bond distances as in ordinary cubic diamond Si, but form 12- and 14-hedral cages which are linked by shared faces. The metal atoms are located in the center of the polyhedra. This is the first superconductor consisting of a Si ${\mathrm{sp}}^{3}$ covalent network.

/pdf/superconductivity-in-the-silicon-clathrate-compound-na-ba-5gbv29iuyt.pdf

Superconductivity in the silicon clathrate compound (Na,Ba)xSi46

A new silicon clathrate compound with a composition of Ba8Si46 was prepared under high-pressure and high-temperature conditions. The compound was isomorphous with Na8Si46 and became a superconductor with a transition temperature of 8.0 K. Barium atoms occupy all of the Si20 and Si24 cages of the clathrate structure. This is the first clathrate superconductor obtained as a bulk phase.

High-pressure synthesis of a new silicon clathrate superconductor, Ba8Si46.

Photochemical and photocatalytic properties of microcrystalline TiO{sub 2} incorporated in the interlayer space of montmorillonite were investigated in reference to those of TiO{sub 2} powder particles which were prepared by agglomeration of a titania sol that was used in the preparation of the titania-pillared clay. The pillared TiO{sub 2} microcrystallites having ca. 15-{angstrom} pillar height showed a ca. 0.58-eV blue shift in its absorption and fluorescence spectra compared with those of the TiO{sub 2} particles, exhibiting the quantum size effect. The excited electronic states of the pillared TiO{sub 2} were determined to be 0.36 V more negative than that of the TiO{sub 2} powder particles. Photocatalytic activities of the pillared TiO{sub 2} were greater than those of the TiO{sub 2} powder particles for decomposition of 2-propanol to give acetone and hydrogen and of n-carboxylic acids with up to eight carbons (from acetic acid to caprylic acid) to give the corresponding alkanes and carbon dioxide, though the pillared TiO{sub 2} exhibited lower activities for decomposition of capric acid, having 10 carbons in a molecule.

Shoji Yamanaka

Papers

Superconductivity at 25.5 K in electron-doped layered hafnium nitride

Superconductivity in the silicon clathrate compound (Na,Ba)xSi46

High-pressure synthesis of a new silicon clathrate superconductor, Ba8Si46.

Photocatalytic activities of microcrystalline titania incorporated in sheet silicates of clay

Preparation and properties of titania pillared clay