Anran Guo

Fabrication of NiCo2O4 and carbon nanotube nanocomposite films as a high-performance flexible electrode of supercapacitors

Herein, we demonstrated facile fabrication of NiCo2O4 nanoparticles on a CNT film by a chemical deposition method, followed by thermal annealing treatment processing. The synthesized NiCo2O4/CNT nanocomposite films were still highly flexible, porous, and conductive. Scanning electrical microscopy (SEM) and transmission electronic microscopy (TEM) observation showed that the web-like structure of the films is still preserved and each carbon nanotube in the film was uniformly wrapped by ball-like nanoparticles (ca. 5 nm). X-Ray Diffraction (XRD) measurement confirmed that spinel NiCo2O4 was successfully synthesized during the experiment. The contents of NiCo2O4 in the composite films could be controlled by tuning the deposition times. The flexible, porous and conductive nanocomposite films could be employed as high-performance flexible energy saving installments. The three-pole measurements illustrated that the composite films possessed a capacitance of 828 F g−1 at 1 A g−1, and retained over 99% of their capacitance after 3000 cycles of charge/discharge at 5 A g−1, showing high-performance electrochemical properties. Finally, an asymmetric supercapacitor installment was assembled by using the composite film as the positive electrode and commercially available activated carbon (AC) as the negative electrode. The measurement gave an energy density of 28.58 W h kg−1 at a power density of 0.7 kW kg−1.

Facile synthesis of free-standing Fe2O3/carbon nanotube composite films as high-performance anodes for lithium-ion batteries

Continuous Fe nanoparticles (NPs)/carbon nanotube (CNTs) composite films have been fabricated with the CVD gas flow reaction using ferrocene as a catalyst and ethanol as a carbon precursor. The as-spun Fe NPs/CNTs films are converted to Fe2O3 NPs/CNTs films by an annealing process in air at a temperature of 500 °C. The as-prepared Fe2O3 NPs/CNTs films are still highly flexible. Scanning electron microscopy (SEM) and transmission electron microscopy observations reveal the Fe2O3 NPs are homogeneously bonded with the CNT network. In addition, the flexible and conductive 3D CNTs networks endow the as-synthesized composite with increased electrical conductivity and mechanical stability. As a result, the as-synthesized flexible and transferrable composite films deliver an initial reversible capacity of 985.8 mA h g−1 at a current density of 30 mA g−1, and maintain a high reversible capacity of 392.4 mA h g−1 even at a current density up to 3 A g−1. Meanwhile, Fe2O3 NPs/CNTs films exhibit an excellent cycling performance with a reversible capacity of 375.5 mA h g−1 after 800 cycles at a current density of 3 A g−1.

Joining of silicon carbide by a heat-resistant phosphate adhesive

In this paper, SiC was bonded with a phosphate inorganic adhesive prepared from H3PO4 and Al(OH)3 as the matrix and Si and B4C as the inorganic fillers. The properties of the obtained adhesive were analyzed by XRD, TG-DSC, IR, shear strength tests and SEM. The results showed that the phosphate adhesive exhibited outstanding heat-resistant properties and excellent bonding strength. The addition of B4C could greatly improve the adhesives mechanical properties due to the formation of borosilicate glass and the volume compensation came from B4Cs oxidation. The shear strength of bonded specimens could be up to about 10 MPa after heat treatment at 1300 °C, attributed to the generation of mullite and borosilicate as well as the reasonable compensation for the adhesives volume.

Preparation and Mechanical Properties of Continuous Carbon Nanotube Networks Modified Cf/SiC Composite

Continuous carbon nanotube (CNT) networks were formed in Cf/SiC composites via freeze-drying method. Composites were fabricated by precursor infiltration and pyrolysis (PIP) process afterwards. The different distribution morphologies of CNTs in the preforms originating from the different CNT contents were analyzed while the influence of the distribution of CNTs was discussed in detail. Compared to composites without CNTs, the interfacial shear strength (ILSS) and the flexural strength of Cf/1%CNTs/SiC were increased by 31% and 27%, respectively, but the values of Cf/2.5%CNTs/SiC decreased as a result of lots of defects caused by excess CNTs. With the analysis of ILSS, the flexural strengths, and the fracture morphologies, CNTs effectively improved the weak interfacial strength between T700SC carbon fibers and SiC matrix.