Synthesis and electrochemical properties of polyaniline nanofibers by interfacial polymerization.

Polyaniline nanofibers were prepared by interfacial polymerization with different organic solvents such as chloroform and carbon tetrachloride. Field emission scanning electron microscopy and transmission electron microscopy were used to study the morphological properties of polyaniline nanofibers. Chemical characterization was carried out using Fourier transform infrared spectroscopy, UV-Vis spectroscopy, and X-ray diffraction spectroscopy and surface area was measured using BET isotherm. Polyaniline nanofibers doped with lithium hexafluorophosphate were prepared and their electrochemical properties were evaluated.

Low-temperature catalytic aqueous phase oxidation of microcystin-LR with iron-doped TiO2 pillared clay catalysts.

TiO2-PILCs and iron-doped TiO2-PILCs were employed in order to destroy toxic microcystin-LR in the presence of H2O2 under the UV light. While less than 5% of the initial microcystin-LR and TOC disappeared in 240 min with the TiO2-PILCs, almost complete conversion of microcystin-LR could be achieved in 180 min on the 10 wt% iron-doped TiO2-PILC-A. On the exterior surface of the iron-doped TiO2-PILCs were mainly located iron particles which had nano-sized diameter and Fe2+/Fe3+ cations together. Through Fenton-type oxidation on iron particles with H2O2, the big microcystin-LR molecules were converted primarily into smaller intermediate organic molecules of hydrocarbons, carboxylic acids and organic amines. The smaller intermediate molecules were believed to be diffused into the pores of the iron-doped TiO2-PILCs and to be further mineralized into CO2 and H2O through the action of photocatalysis on the TiO2 pillars. However, complete conversion of TOC could not be obtained due to the iron particle deactivation. XPS, TPO and TEM studies showed the continuous accumulation of carbonaceous materials onto the surface of iron particles.

Heating effect on physical and electrochemical properties of nanofibrous polyacrylonitrile separator for lithium batteries.

Nanofibrous polyacrylonitrile (PAN) membranes as nonwoven separators were prepared by electrospinning followed by a thermal treatment to improve their physical properties. The effect of the thermal treatment on the physical and electrochemical properties of the PAN separators was investigated. With increasing heating time, the PAN nanofiber separators became denser with decreasing size of fully interconnected pores. The tensile strength and modulus of the nanofibrous PAN separators varied with the heating temperature and heating time. The maximum tensile strength and modulus were obtained at a heating temperature and heating time of 170 degrees C and 5 h, respectively. The cell assembled with the PAN separator prepared at 170 degrees C for 5 h exhibited high capacity retention and stable cycle performance, even at higher discharge current densities.

Structural characterization and electrochemical properties of Co3O4 anode materials synthesized by a hydrothermal method.

Cobalt oxide [Co3O4] anode materials were synthesized by a simple hydrothermal process, and the reaction conditions were optimized to provide good electrochemical properties. The effect of various synthetic reaction and heat treatment conditions on the structure and electrochemical properties of Co3O4 powder was also studied. Physical characterizations of Co3O4 are investigated by X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller [BET] method. The BET surface area decreased with values at 131.8 m2/g, 76.1 m2/g, and 55.2 m2/g with the increasing calcination temperature at 200°C, 300°C, and 400°C, respectively. The Co3O4 particle calcinated at 200°C for 3 h has a higher surface area and uniform particle size distribution which may result in better sites to accommodate Li+ and electrical contact and to give a good electrochemical property. The cell composed of Super P as a carbon conductor shows better electrochemical properties than that composed of acetylene black. Among the samples prepared under different reaction conditions, Co3O4 prepared at 200°C for 10 h showed a better cycling performance than the other samples. It gave an initial discharge capacity of 1,330 mAh/g, decreased to 779 mAh/g after 10 cycles, and then showed a steady discharge capacity of 606 mAh/g after 60 cycles.