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A new method, which combines non-equilibrium plasma reaction with template-controlled growth technology, has been developed for synthesizing aligned carbon nanotubes at atmospheric pressure and low temperature. Multiwall carbon nanotubes with diameters of approximately 40 nm were restrictedly synthesized in the channels of anodic aluminum oxide template from a methane/hydrogen mixture gas by a.c. corona discharge plasma reaction at a temperature below 200 °C. It was observed that amorphous carbon deposited on the tops of the carbon nanotubes. The formation mechanism of carbon nanotubes synthesized by corona discharge plasma method was discussed. [Copyright &y& Elsevier]

Carbon nanowires (CNWs) have been template-directed synthesized from methane and hydrogen mixtures through pulsed corona plasma reaction. The products were analyzed by transmission electron microscopy, scanning electron microscope and Raman spectroscopy. The results suggested that the CNWs are mainly composed of microcrystalline graphite full of defects. This study provides a new method for synthesizing 1D nanomaterials at atmospheric pressure and low temperature, which has some special advantages for scale-up production or applications. [Copyright &y& Elsevier]

Carbon-coated Li 2 MnSiO 4 nanocrystallites are synthesized via a solid state reaction, and their cathode and anode performance is comparatively studied. The Li 2 MnSiO 4 cathode shows an initial charge/discharge capacity of 405/134 mAh g −1 at a current density of 16.6 mA g −1 , and a low charge/discharge capacity of 93/66 mAh g −1 during the 20th cycle. Partial Li 2 MnSiO 4 cathode decomposes at 4.56 V ( vs Li + /Li) during the initial charge. Interestingly, the Li 2 MnSiO 4 anode exhibits a high initial discharge/charge capacity of 658/388 mAh g −1 at a current density of 20 mA g −1 , and a discharge/charge capacity of 459/456 mAh g −1 during the 50th cycle. Li 2 MnSiO 4 anodes also have stable and good rate capabilities. The Li 2 MnSiO 4 crystallites as anode decompose during cycling, and their capacity increases simultaneously. It is proposed that Li 2 MnSiO 4 anode converts energy via a reversible conversion reaction. [ABSTRACT FROM AUTHOR]

To enhance the rate and cyclic performances of LiMnPO 4 cathode material for lithium-ion batteries, Mn is partially substituted with Fe, and LiMn 1− x Fe x PO 4 ( x = 0.2, 0.3, 0.4, 0.5) solid solutions are synthesized and investigated. Amphiphilic carbonaceous material (ACM) forms well carbon coating and connects the LiMn 1− x Fe x PO 4 crystallites by a three-dimensional (3D) carbon network. The synergetic Fe substitution and carbon connection obviously improve the samples’ rate capacities and cyclic stability. The optimized LiMn 0.6 Fe 0.4 PO 4 /C sample delivers discharge capacities of 160 mA h g −1 at 0.05 C, 148 mA h g −1 at 1 C, and 115 mA h g −1 at 20 C. All samples have well capacity retention (>92%) after 50 charge/discharge cycles at 1 C. The enhanced electrochemical properties are mainly attributed to the improvement of Li ion and electron transport in the LiMn 1− x Fe x PO 4 /C samples, respectively mainly resulting from their modified crystal structures caused by Fe substitution and the 3D carbon coating/connection originating from ACM carbonization. LiMn 1− x Fe x PO 4 materials exhibit two discharge plateaus at ∼4.0 and ∼3.5 V (vs. Li + /Li), whose heights respectively reflect the redox potentials of Mn 3+ /Mn 2+ and Fe 3+ /Fe 2+ couples. The plateaus’ lengths correspond to the Mn/Fe ratio in LiMn 1− x Fe x PO 4 and are affected by the kinetic behavior of samples. Though the ∼4.0 V plateau shrinks with increasing discharge rate, the ∼3.5 V plateau may slightly elongate. Moreover, the Fe substituted in the partial Mn sites could significantly improve the Li ion diffusion, thus enhance the kinetic behaviors of LiMn 1− x Fe x PO 4 . [ABSTRACT FROM AUTHOR]

The synthesis of conductive composites consisting of waterborne polyurethane (WPU) and carbon black (CB) is reported. Besides the low percolation threshold (0.7–0.95 wt%), the composites are quite sensitive to organic solvent vapors regardless of their polarities as characterized by the drastic changes in conductivity. In the case of polar solvents, negative and positive vapor coefficient phenomena of the composites were successively observed with a rise in CB content. It was found that different mechanisms are responsible for the broad applicability of the composites as candidates for gas sensing materials owing to the different interactions among the matrix polymer, the filler particles and the solvent molecules. [Copyright &y& Elsevier]