Raman study of lithium coordination in EMI‐TFSI additive systems as lithium‐ion battery ionic liquid electrolytes

Raman spectroscopy was performed on various mixtures of the ionic liquid salt, 1‐ethyl‐3‐methylimidazolium‐bis(trifluoromethylsulfonyl)imide (EMI‐TFSI). When EMI‐TFSI is used in combination with a lithium salt, it could be a potential electrolyte for lithium‐ion or lithium metal batteries. The Raman spectra of EMI‐TFSI, EMI‐TFSI 0.5 M Li‐TFSI, EMI‐TFSI 0.5 M Li‐TFSI 2 M vinylene carbonate (VC) and EMI‐TFSI 0.5 Li‐TFSI 2 M ethylene carbonate (EC) were collected and compared. A comparison of the peak positions of the δ_s CF₃ mode at 742 cm⁻¹ demonstrates that when carbonate additives are present, the lithium ion is no longer interacting with the TFSI anion. Instead, it is coordinated with the carbon–oxygen double bond of the carbonates. Copyright © 2006 John Wiley & Sons, Ltd.     

Modelling and control of natural convection in canned foods

In this paper we study mathematically an industrial problemrelated to sterilization processes involving heat transfer bynatural convection. We give results of existence and regularityfor the solution of this problem. We recast the whole problemas an optimal control problem with pointwise constraints onthe state and the control in order to ensure the reduction ofmicroorganism concentration and the retention of nutrients,and to save energy. Finally, we give results on existence ofthe optimal solution and optimality conditions for its characterization.     

The Addition of Nitriles to a Molecular Digermene: Reversible Addition and Comparison to Surface Reactivity

The addition of acetonitrile, propionitrile, and acrylonitrile to tetramesityldigermene was investigated and compared to the addition of acetonitrile and acrylonitrile to germanium dimers on the Ge(100)‐2×1 surface. In each case, a 1,2,3‐azadigermetine was formed as the major product. As on the surface, the addition of nitriles to digermenes was found to be reversible, providing the first example of a reversible cycloaddition of a ditetrelene. No evidence for a six‐membered cyclic ketenimine was observed as noted in the surface chemistry, suggesting that the surface ketenimine might only form between two adjacent dimers rather than on a single dimer. The comparative chemistry provides important insights that are not possible by the independent study of each system.     

Ion Exchange in Hydrometallurgical Processing: An Overview and Selected Applications

Ion exchange has traditionally been employed for the purification of water and the removal of metal contaminants from dilute waste streams. More recently, its use in removing trace metallic impurities from hydrometallurgical process streams (with typical background metal concentrations of 50–100 g/L) has increased substantially. It is also used as a primary recovery and concentration unit operation for certain commodities, where both technical and cost advantages become apparent for complex flow sheets. This overview discusses selected modern applications of ion exchange in hydrometallurgical processes for uranium, precious metals, copper, cobalt, nickel and zinc, and identifies some opportunities for the future.     

Direct detection of discharge products in lithium-oxygen batteries by solid-state NMR spectroscopy

A closer look: Solid-state (7) Li and (17) O?NMR spectroscopy is a valuable tool in the characterization of products formed in the lithium-oxygen battery, a necessary step in the development of a viable cell. Since lithium peroxide, the desired discharge product, has a unique (17) O?NMR signature, it can be clearly identified.     

Polarisation parameters in positive pion photoproduction

Measurements have been made of the polarisation parameters Σ, T and P for the process γp → π⁺n in the photon energy range 520–2250 MeV at c.m. angles between 30° and 120°. These data were obtained in a double polarisation experiment, using the polarised photon beam from the Daresbury electron synchrotron incident on a polarised proton target. The data are compared with predictions from current theoretical analyses.