Synthesis and Field Emission Properties of Carbon Nanowire-Single Walled Carbon Nanotube Networks Hybrid Films

Carbon nanowire (CNW)-singlewalled carbon nanotube (SWCNT) networks hybrid films with a large area (~400 mm2) are grown on molybdenum (Mo) layers by microwave plasma chemical vapour deposition system. The Mo layers, which were deposited on Al2O3 ceramic substrates through electron beam evaporation deposition, were pretreated by a laser-grooving (LG) technology. Furthermore, the surface morphology, micro-structure and field emission properties of these samples are characterized by scanning electron microscope, Raman spectra, and field emission I - V measurements. ACNW-SWCNT networks hybrid film was formed in the surface of Mo layer, but the laser etched area (linear pits array area) the distribution of the CNW-SWCNT networks density is lower than the un-etched area CNW-SWCNT networks distribution density. The diameter of the CNWs and SWCNTs, respectively in the 8 - 15 nm and 0.9 - 1.5 nm range, and the length of CNW-SWCNTs ranges from 1 μm to 4 μm. The growth mechanisms of the films were discussed. Effects of LG pretreatment on surface morphologies and microstructure of the hybrid films were investigated. The field electron emission experimental results shown that the ture on field as low as 1.6 V/μm, and a current density of 0.15 mA/cm2 at an electric field of 4.3 V/μm was obtained.

Fluorinated graphene nanoribbons from unzipped single-walled carbon nanotubes for ultrahigh energy density lithium-fluorinated carbon batteries

Lithium-fluorinated carbon(Li-CFx)batteries have become one of the most widely applied power sources for high energy density applications because of the advantages provided by the CFx cathode.Moreover,the large gap between the practical and theoretical potentials alongside the stoichiometric limit of commercial graphite fluorides indicates the potential for further energy improvement.Herein,monolayer fluorinated graphene nanoribbons(F-GNRs)were fabricated by unzipping single-walled carbon nanotubes(SWCNTs)using pure F2 gas at high temperature,which delivered an unprecedented energy density of 2738.45 W h kg^(−1)due to the combined effect of a high fluorination degree and discharge plateau,realized by the abundant edges and destroyed periodic structure,respectively.Furthermore,at a high fluorination temperature,the theoretical calculation confirmed a zigzag pathway of fluorine atoms that were adsorbed outside of the SWCNTs and hence initiated the spontaneous process of unzipping SWCNTs to form the monolayer F-GNRs.The controllable fluorination of SWCNTs provided a feasible approach for preparing CFx compounds for different applications,especially for ultrahigh-energy-density cathodes.