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Significant capacity losses are generally seen for batteries containing high-capacity lithium alloy forming anode materials such as silicon, tin and aluminium. These losses are generally ascribed to a combination of volume expansion effects and irreversible electrolyte reduction reactions. Here, it is shown, based on e.g. elemental analyses of cycled electrodes, that the capacity losses for tin nanorod and silicon composite electrodes in fact involve diffusion controlled trapping of lithium in the electrodes. While an analogous effect is also demonstrated for copper, nickel and titanium current collectors, boron-doped diamond is shown to function as an effective lithium diffusion barrier. The present findings indicate that the durability of lithium based batteries can be improved significantly via proper electrode design or regeneration of the used electrodes. © The Royal Society of Chemistry 2017.

Aerospace Structures and Materials, Aerospace Engineering

This work describes a method to produce microstructured PDMS stamps that are metallized in two isolated sections, thus creating the possibility to electroprint a surface using such a stamp as both counter electrode and reference electrode in a surface con

Constant potential coulometry in combination with cyclic voltammetry, UV-Vis, H-1 and C-13 NMR spectroscopy were used to identify the oxidation and reduction products for some structurally similar azosalicylic acids, including the azosalicylic drugs Sulfa, Addresses: Nyholm L, Uppsala Univ, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

The influence of the separation voltage on end column electrochemical detection (EC) in capillary electrophoresis (CE) has been investigated using an electrochemical detector chip based on an array of microband electrodes. It is shown, both theoretically, Addresses: Nyholm L, Uppsala Univ, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

The processes that cause the failure of sheathless electrospray ionization (ESI) emitters, based on different kinds of gold coatings on fused-silica capillaries, are described and explained. The methods chosen for this study include electrochemical method, Addresses: Nyholm L, Uppsala Univ, Dept Analyt Chem, Box 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Mat Sci, SE-75121 Uppsala, Sweden. Linkoping Univ, Dept Phys & Measurement Technol, Div Ap

The influence of convection on the degree of redox cycling at interdigitated microarray electrodes in a flow system was investigated in the end column detection mode for flow rates below 20 mu L/min. It was found that the degree of redox cycling increased, Addresses: Nyholm L, Uppsala Univ, Inst Chem, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Inst Chem, Dept Analyt Chem, SE-75121 Uppsala, Sweden. Uppsala Univ, Angstrom Lab, Dept Mat Sci, SE-75121 Uppsala, Sweden.

The atmospheric pressure ionization process obtained when a mixture of methanol and water (90:10, v/v) also containing 50 mu m sodium hydroxide is dispersed from a fused-silica emitter was studied, A combination of a high electric held and a nebulizer gas, Addresses: Markides KE, Uppsala Univ, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

The formation of self-assembled chemisorbed layers of cystamine, cysteamine, and 4-aminothiophenol on gold has been studied by XPS and voltammetry. These compounds, often used in the preparation of biosensors and modified electrodes, are shown to yield surface coverages of approximately 80% of that of a octadecanethiol monolayer within 5 min in millimolar aqueous and ethanolic solutions. The results of the XPS experiments reveal that a shoulder on the S 2p(3/2) peak (situated at 162.1 eV) develops at 161.3 eV upon increasing the adsorption time from minutes to 1 week and that the initial rate of formation of the shoulder is higher for cystamine than for cysteamine. This shoulder is believed to be due to the presence of a sulfur species with a higher coordination number with respect to gold. Increased adsorption times also give rise to increased amounts of oxidized carbon and sulfur in the films. The oxidation of the sulfur in the thiols results in a detachment of the molecules from the gold surface, as indicated by XPS experiments with different takeoff angles. The main N 1s peak for cystamine is shifted toward higher binding energies for increasing adsorption times while two prominent nitrogen peaks are generally seen for cysteamine. For cysteamine, increasing adsorption times result in an increase of the main nitrogen component at the higher binding energy, yielding an apparent shift in the nitrogen peak with time similar to that seen for cystamine. Possible explanations for these experimental findings are discussed. Cystamine, cysteamine, and 4-aminothiophenol films on gold are shown to be irreversibly oxidized in the gold oxide formation region. On the basis of evaluation of the oxidation charge, surface coverages of approximately 1 x 10(-9) mol/cm(2) were obtained for adsorption times between 5 min and 1 week., Addresses: Wirde M, Univ Uppsala, Dept Phys, Box 530, SE-75121 Uppsala, Sweden. Univ Uppsala, Dept Phys, SE-75121 Uppsala, Sweden. Univ Uppsala, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

End-column electrochemical detection based on either the use of a 25 mu m microdisk electrode or a 0.5 mm macrodisk electrode has been compared with respect to performance and influence on non-aqueous capillary electrophoretic separations. Despite the mu, Addresses: Nyholm L, Uppsala Univ, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden. Univ Leipzig, Inst Analyt Chem, D-04103 Leipzig, Germany.

Amperometric determinations of the water content in acetone, butter and margarine were performed using a wall-tube platinum microelectrode in combination with a flow injection system. For the butter and margarine samples, acetone containing small amounts, Addresses: Nyholm L, Uppsala Univ, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden. Univ Warsaw, Dept Chem, PL-02093 Warsaw, Poland.

A recently developed microelectrochemical detector for packed capillary column supercritical fluid chromatography (pcSFC) has been applied to determine nanogram amounts of tocopherols and vitamin A in vegetable oil samples. With this procedure, no remova, Addresses: Nyholm L, Univ Uppsala, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Univ Uppsala, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

Microfabricated arrays consisting of four individually addressable band electrodes have been used for end-column electrochemical detection in capillary electrophoresis (CE), The commercially available array was positioned 75-300 mu m from the capillary o, Addresses: Nyholm L, Univ Uppsala, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Univ Uppsala, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

The electrochemical properties of a number of azosalicylic acid derivatives have been compared at glassy carbon electrodes using cyclic and hydrodynamic voltammetry. The reduction of all studied compounds, except one, was found to be irreversible giving, Addresses: Nyholm L, Uppsala Univ, Dept Analyt Chem, Inst Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, Inst Chem, SE-75121 Uppsala, Sweden.

Capillary electrophoresis (CE) was coupled to a microelectrode-based end-column amperometric detector. The influences of separation voltage, CE buffer concentration, and capillary-to-electrode distance on the observed hydrodynamic voltammetry of dopamine, Addresses: Lunte CE, Univ Kansas, Dept Chem, Lawrence, KS 66045 USA. Univ Kansas, Dept Chem, Lawrence, KS 66045 USA. Univ Uppsala, Dept Analyt Chem, S-75121 Uppsala, Sweden.

The current response of a 10-mu m walt-tube microelectrode in a now injection system under the conditions of low ionic strength has been examined experimentally for several redox systems such as ferrocene in methanol, undiluted methanol, and water in ace, Addresses: Stojek Z, Univ Warsaw, Dept Chem, Pasteura 1, PL-02093 Warsaw, Poland. Univ Warsaw, Dept Chem, PL-02093 Warsaw, Poland. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

The oxidation behavior of 3-aminosalicylic acid (3-ASA), 4-aminosalicylic acid (4-ASA) and 5-aminosalicyclic acid (5-ASA), the active part of the drugs Sulphasalazine and Dipentum for the treatment of ulcerative colitis, has been compared. The redox beha, Addresses: Nyholm L, Uppsala Univ, Inst Chem, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Inst Chem, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

A new polymer, polymethacryloxypropylhydrosiloxane (PMAHS), has been developed and used as both a deactivating layer and an intermediate layer for stable coating of an uncharged polymer on fused silica capillaries in capillary electrophoresis. The deactiv, Addresses: UNIV UPPSALA, S-75121 UPPSALA, SWEDEN. PHARMACIA & UPJOHN INC, BIOPHARMACEUT, S-11287 STOCKHOLM, SWEDEN.

An end-column microelectrochemical detector, based on a 25 mu m platinum electrode, was used in miniaturised flow and separation systems, at linear mobile phase velocities below 0.1 cm s(-1) (i.e. a volumetric flow of a few mu l min(-1) for a 200 mu m i, Addresses: UNIV UPPSALA, DEPT ANALYT CHEM, S-75121 UPPSALA, SWEDEN.

Oxidative and reductive amperometric detection of phenols, nitroaromatic compounds and a cyclic ketone is demonstrated in packed capillary column supercritical fluid chromatography (SFC). The detection was performed in combination with isobaric, as well, Addresses: UPPSALA UNIV, DEPT ANALYT CHEM, S-75121 UPPSALA, SWEDEN.

Amperometric detection at a naked platinum microelectrode is shown to be compatible with pressure-programmed packed capillary column supercritical fluid chromatography (SFC) using carbon dioxide modified with as little as 1% acetonitrile, Amperometric de, Addresses: UNIV UPPSALA, DEPT ANALYT CHEM, S-75121 UPPSALA, SWEDEN.

Electrochemical detection of disodium 3,3'-azobis-(6-hydroxy-)benzoate, olsalazine sodium, in reversed phase Liquid chromatography is shown to provide a detection limit of 40 fmol and a linear range extending up to 4 nmol for an injection volume of 20 mu, Addresses: Nyholm L, Uppsala Univ, Inst Chem, Dept Analyt Chem, POB 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Inst Chem, Dept Analyt Chem, SE-75121 Uppsala, Sweden.

Six different cyclodextrins with varying cavity size and rim substitution were used as chiral agents for the enantiomeric separation of eight chromane compounds or analogues using capillary electrophoresis. It is shown that the cyclodextrin type and conc, Addresses: UNIV UPPSALA, DEPT ANALYT CHEM, S-75121 UPPSALA, SWEDEN. VITAMIN RES & TECHNOL DEV, CH-4070 BASEL, SWITZERLAND. F HOFFMANN LA ROCHE & CO LTD, PHARMA RES NEW TECHNOL, CH-4070 BASEL, SWITZERLAND. HEWLETT PACKARD SWEDEN, CHEM ANAL GRP, S-16427 KI

A flow system is described in which stable preplated mercury coatings on microelectrodes can be obtained due to minimised handling of the electrode and the fact that potentiostatic control can be maintained also between the experiments. Compared to the d, Addresses: UNIV UPPSALA, INST CHEM, DEPT ANALYT CHEM, S-75121 UPPSALA, SWEDEN.