Search

Abstract: Strontium ferrite particles were firstly prepared by sol–gel method and self-propagating synthesis, and then the polyaniline/strontium ferrite/multiwalled carbon nanotubes composites were synthesized through in situ polymerization approach. Structure, morphology and properties of the composite were characterized by various instruments. XRD analysis shows that the output of PANI increases with the increase of the content of MWCNTs, due to the large surface area of MWCNTs. Because of the coating of PANI, the outer diameter of MWCNTs increases from 10nm to 20–40nm. The electrical conductivity of the composites increases with the amount increase of MWCNTs and reaches 7.2196S/cm in the presence of 2g MWCNTs. The coercive force of the composites prepared with 2g MWCNTs is 7457.17Oe, which is much bigger than that of SrFe12O19 particles 6145.6Oe, however, both the saturation magnetization and the remanent magnetization of the composite become much smaller than those of SrFe12O19 particles. The electromagnetic properties of the composite are excellent in the frequency range of 2–18GHz, which mainly depend on the dielectric loss in the range of 2–9GHz, and mainly on the magnetic loss in the range of 9–18GHz. [Copyright &y& Elsevier]

Highlights: [•] Graphene was grown on Cu foil by mobile thermal chemical vapor deposition system. [•] CNT was synthesized on graphene for RuO2 nanostructure growth by thermal chemical vapor deposition system. [•] The CNT growth location was fixed through the use of photolithography technique, thereby increasing the specific area. [•] RuO2 nanostructures were coated onto CNT bundle arrays through metal organic chemical vapor deposition, in order to utilize its pseudo capacitive property. [ABSTRACT FROM AUTHOR]

The carbon nanotube (CNT) has replaced palladium oxide (PdO) as the electrode material for surface-conduction electron-emitter (SCE) applications. Vertically aligned CNT arrays with a delta-star arrangement were patterned and synthesized onto a quartz substrate using photolithography and thermal chemical vapor deposition. Delta-star shaped VACNT arrays with 20° tips are used as cathodes that easily emit electrons because of their high electrical field gradient. In order to improve the field emission and secondary electrons (SEs) in SCE applications, magnesium oxide (MgO) nanostructures were coated onto the VACNT arrays to promote the surface-conduction electron-emitter display (SED) efficiency (η). According to the definition of η in SCE applications, in this study, the η was stably maintained in the 75–85% range. The proposed design provides a facile new method for developing SED applications. [ABSTRACT FROM AUTHOR]

Amorphous carbon nanorods (CNRs) were deposited directly using radio frequency magnetron sputtering. The synthesized CNR electrochemical properties were investigated using graphene as the current collector for an electric double layer capacitor. The CNRs were vertically aligned to the graphene to achieve higher specific surface area. The capacitor performance was characterized using electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge testing in 1 M KOH electrolyte at 30°C, 40°C, 50°C, and 60°C. The CNR specific capacitance was observed to increase with increasing measurement temperature and could reach up to 830 F/g at 60°C. Even after extensive measurements, the CNR electrode maintained good adhesion to the graphene current collector thereby suggesting electrode material stability. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanotubes (CNTs) were used as the electric double layer capacitor (EDLC) material and were synthesized by using thermal chemical vapor deposition (TCVD). To enhance the EDLC capacity, the ruthenium dioxide (RuO2) nanorods were grown on CNTs by using metal organic chemical vapor deposition (MOCVD). The synthesized CNTs were the principal part and template, and the RuO2 nanorods were grown outwardly from CNTs. The increase of effective specific area between electrode and electrolyte played an important role in enhancing the capacitance. Different concentrations of KOH were used as electrolyte to measure the capacitance to find the variation of capacitance. Moreover, the RuO2/CNT composites demonstrated a stable cycle life. The results showed that the RuO2/CNT composites were a promising supercapacitor device material. [Copyright &y& Elsevier]