A different method for producing a flexible LiMn2O4/MWCNT composite electrode for lithium ion batteries

A flexible lithium manganese oxide (LiMn₂O₄)/multi-wall carbon nanotube (MWCNT) composite electrode was produced by casting a slurry-containing powdered LiMn₂O₄ on a previously prepared MWCNT paper. The structure of this new LiMn₂O₄/MWCNT composite electrode was characterized using scanning electron microscopy and X-ray diffraction patterns. Furthermore, the surfaces of these electrodes were coated with gold–palladium alloy using an RF magnetron sputtering technique to prevent Mn dissolution. To investigate the electrochemical performance of this flexible LiMn₂O₄/MWCNT composite electrode, a bare-LiMn₂O₄ electrode was prepared. The discharge capacity of the produced LiMn₂O₄/MWCNT nanocomposite electrode was cyclically tested, and the charge transfer resistance of the electrodes was studied using electrochemical impedance spectroscopy. Consequently, the Au–Pd-coated LiMn₂O₄/MWCNT had a 120 mAh g^?1 discharge capacity and 90 % capacity retention after 100 cycles.     

Immobilisation of β-galactosidase onto gelatin by glutaraldehyde and chromium(III) acetate

β-Galactosidase (EC 3.2.1.23) was immobilised onto a gelatin carrier system by crosslinking. Glutaraldehyde and chromium(III) acetate were used as crosslinking agents. The effect of pH on enzyme activity, kinetic parameters and reusability of the immobilised enzyme were investigated. To obtain a better relative activity, a method was developed and further modified to increase the surface area of the support system by using polyacrylamide. Relative activity enhancement of 68% was achieved in the gelatin–glutaraldehyde system.     

Radiation-induced and electroinitiated polymerisation of 1, 2-Epoxy-4-epoxyethylcyclohexane

Liquid state radiation-induced and electroinitiated cationic polymerisation of 1,2-epoxy-4-epoxyethylcyclohexane (EECH) have been investigated. Soluble and cross-linked polymers were obtained during the radiation-induced polymerisation of EECH, depending upon the radiation dose. Electroinitiated polymerisation of the monomer yielded cross-linked polymers on the surface of the anode. The expected polyether structure was observed for i.r. data. The polymerisation propagates via opening of the epoxy rings as indicated by n.m.r. spectra. X-Ray analyses showed that the products obtained by both methods are amorphous.     

Superwetting nanowire membranes for selective absorption

The construction of nanoporous membranes is of great technological importance for various applications, including catalyst supports, filters for biomolecule purification, environmental remediation and seawater desalination. A major challenge is the scalable fabrication of membranes with the desirable combination of good thermal stability, high selectivity and excellent recyclability. Here we present a self-assembly method for constructing thermally stable, free-standing nanowire membranes that exhibit controlled wetting behaviour ranging from superhydrophilic to superhydrophobic. These membranes can selectively absorb oils up to 20 times the material's weight in preference to water, through a combination of superhydrophobicity and capillary action. Moreover, the nanowires that form the membrane structure can be re-suspended in solutions and subsequently re-form the original paper-like morphology over many cycles. Our results suggest an innovative material that should find practical applications in the removal of organics, particularly in the field of oil spill cleanup.     

Tribological Properties of TiO<Subscript>2</Subscript> Reinforced Nickel Based MMCs Produced by Pulse Electrodeposition Technique

Nickel–TiO₂ composite coatings were prepared under pulse current conditions by co-deposition of TiO₂ particles and nickel from a Watts type bath. The effect of TiO₂ particle concentration was studied on microhardness, friction coefficient and wear resistance. The morphological features and the structures were studied by scanning electron microscope, X-ray diffraction analysis and 3D profilometry facilities. A wide particle size range (between 95 and 140 nm) was chosen to provide a high dispersion and load bearing ability for the co-deposited layers. It was determined that increasing the particle concentration in the electrolyte dramatically increased the co-deposited TiO₂ particles in the coating. The results showed that the high concentration of TiO₂ particles in the electrolyte yielded the highest amount of particles co-deposited in the plating layer. The influence of the co-deposited TiO₂ volume on microstructure and tribological properties in the coating were investigated. The wear tests were carried out using a constant load by a reciprocating ball-on disk configuration. Wear loss and friction coefficients of Ni/TiO₂ composites were decreased by increasing TiO₂ content in the electrolyte because of the increasing content of TiO₂ in the deposited layer. The change in wear mechanisms by changing TiO₂ content was also determined.