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Carbon nanotubes, which consist of rolled graphene sheets built from sp(2) hybridized carbon atoms, are now attracting scientists from various disciplines due to their fascinating physico-chemical properties. In this account, we will review the recent progress on the synthetic techniques for the large-scale production of carbon nanotubes, especially focusing on the floating-catalyst method used in the chemical vapour deposition (CVD) process. We will also describe effective purification methods avoiding structural damage, and discuss the electrochemical applications of these systems including the fabrication of: (i) lithium-ion secondary batteries; (ii) lead-acid batteries; (iii) electric double-layer capacitors; (iv) fuel cells; and (v) multifunctional fillers in polymer composites. We foresee that carbon nanotubes will find numerous applications and take an important place in the development of emerging technologies in the near future.

Here we fabricated rubber composite sheets filled with 5wt% and 30wt% of highly aligned carbon nanotubes (CNTs) through conventional rubber technology. The alignment of CNTs was possibly derived from dragged shear force during the optimized milling process. The selective alignment of CNTs leaded to enhancement of elastic modulus, thermal conductivity, electrical conductivity, and electromagnetic shielding property compared to neat rubber sheet.

This study demonstrates the ability to fabricate lightweight, ductile but mechanically strong magnesium alloy (AZ91D) composites by introducing a small number of high crystalline multi-walled carbon nanotubes. It is demonstrated that 1 % of relatively short and straight carbon nanotubes distributed homogeneously on the outer surface of magnesium powders act as an effective reinforcing filler to prevent deformation, thereby contributing to the enhanced tensile strength of magnesium alloy composites (e.g., from 315 to 388 MPa).Keywords: Carbon nanotubes; Magnesium alloy; Powder processing; Mechanical property There has been strong recent interest in developing lightweight and high-strength materials to improve the energy-efficiency through the weight reduction of automobiles and aircrafts. For these purposes, magnesium alloys have attracted a lot of attention [1-3], as they have low density in its purest form, and in addition, they have been proved to have good mechanical properties through the incorporation of structural filler (e.g., silicon carbide whisker, aluminum and graphite particles, and carbon fibers) [4][5][6][7]. Within this context, the dimensionally nano-sized, mechanically strong, electrically and thermally conductive carbon nanotubes [8][9][10][11], considered to be the ideal reinforcing filler in various composite systems [12][13][14][15], have been incorporated into magnesium matrix [16][17][18][19]. Recently, Goh et al. [19] reported a simple way of preparing nanotube-reinforced magnesium composite by powder-powder mixing and subsequent hot extrusion processes. However, low enhancement (only 5 %), or even a decrease in, tensile strengths in nanotube-reinforced magnesium composites (see Table 3 in ref. 19) could be explained by the presence of aggregated carbon nanotubes within a magnesium matrix. To exploit carbon nanotubes fully as a mechanical reinforcing filler in a magnesium matrix, optimized fabrication processes including homogeneous dispersion of carbon nanotubes must be 1

Arrays of aligned nanotubes of large diameter (100–250 nm) are synthesized by pyrolyzing a jet (spray) solution of Fe(C5H5)2 and C6H6 in an Ar atmosphere at relatively low temperatures (850 °C). The tubular structures consist of highly crystalline nested graphene cylinders (<200 concentric tubes) with tips that are usually open. Raman studies confirm the high degree of perfection of these “thick” structures. Tube diameter, degree of alignment, and crystallinity can be controlled by varying the Ar flow rate and the Fe:C ratio within the precursor solution. Based on these observations a possible growth mechanism is suggested. This low cost route for the synthesis of carbon nanotubes is advantageous due to the absence of H2 as a carrier gas and the low pyrolytic temperature.