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Recently, copper sulfide (CuS) quite arouses researchers' interest due to its high theoretical capacity and excellent electroconductivity. However, poor cycling stability seriously limited the application in supercapacitors. In addition to the improvement of cycling performance, it is also a challenge to develop electrode materials with energy density. Herein, RGO/CuS composite is prepared successfully by solvothermal reaction methods. By the observation using FESEM and TEM, CuS microstructure displays regular and tiny nanoparticles, which are supported by RGO sheets. After the electrochemical measurements, RGO/CuS composite exhibits a maximum specific capacitance of 946 F g−1 at 10 mV s−1 and 906 F g−1 at 1 A g−1, respectively. The excellent cycling stability is also achieved and it maintains 89% retention after 5000 cycles at 5 A g−1. RGO/CuS composite also possesses high energy density of 105.6 W h kg−1 at the power density of 2.5 kW kg−1, which indicates that RGO/CuS composite has a bright future as electrode materials for supercapacitors.

In this work, a long-life and high-performance electrode material is successfully fabricated by the incorporation of carbon nanotube (CNT) with different length using chemical vapor deposition (CVD) on a hierarchically three dimensional (3D) carbon foam (CF), which is obtained from the mesophase pitch. The morphology, composition, and electrochemical performance of the as-prepared composites are characterized using the scanning electron microscope (SEM), Raman spectroscopy, X-ray diffraction (XRD) patterns, cyclic voltammetry, and galvanostatic charge/discharge cycling techniques. Characterizations suggest that this resultant CF/CNT-50 electrode material has a good cycling stability with capacitance retention of 96.5% even after 10000 cycles. Moreover, it shows a high mass capacitance of 227.5 F/g based on the resultant electrode materials, higher energy density of 28 Wh kg−1 and power density of 3700 W kg−1 at a current density 2 A g−1 and also excellent charge/discharge rate. These measured charge storage properties make the proposed hybrid materials excellent electrode material candidates for high performance supercapacitors.

Coiled amorphous carbon nanotube (CACNT) array was prepared by chemical vapor deposition method. The experimental results indicated that the length of as-prepared CACNT array was about 30 μm. The electromagnetic wave absorbing properties were studied through comparison among CACNTs, CACNT-La(NO 3 ) 3 , CACNT-(Fe, Co, Ni) and CACNT-reduced graphene oxide (RGO). The experimental results showed the maximum frequency bandwidth of CACNT-(Fe, Co, Ni) was 6.4 GHz below −5 dB and 2.3 GHz below −10 dB separately. Compared to the pure CACNTs, all the frequency bandwidth had been broaden after adding the modified agent. Meanwhile, the additive of rare earth ions La 3+ could effectively increase the maximum absorption peak (−17.94 dB at 8.96 GHz).

In this work, reduced graphene oxide (RGO) - carbon nanotubes (CNT) grown on carbon fiber (CF) is fabricated by a combination of electrophoretic deposition (EPD) and chemical vapor deposition (CVD). Firstly, CF-GO composite is prepared via EPD. Secondly, the CF-RGO-CNT hybrid is obtained by floating catalyst chemical vapor deposition method for synthesizing CNT on the CF-RGO substrate. The as-prepared three-dimensional (3D) hierarchical hybrid shows strong mechanical stability and high flexibility at various bending angles. Furthermore, the hybrid is characterized by scanning electron microscope, X-ray Diffraction and Raman spectroscopy, and its supercapacitor properties are also tested. The electrochemical measurements display a higher specific capacitance of 203 F g−1, 4 times higher than that of pure CF. Importantly, the hybrid shows high electrochemical stability at various bending angles, and can be directly served as flexible electrode with binder-free for high-performance supercapacitors. All these attractive results indicate that the as-prepared 3D hybrid is a promising candidate for flexible supercapacitor applications.

The reduction of graphene oxide was promoted remarkably under pressure via low temperature thermal treatment. Traditionally, graphene oxide is usually reduced in a preheated high temperature environment as a precondition of the thermal reduction. We report a pressure promoted method for low temperature thermal reduction and exfoliation of graphene oxide in large quantity at 260 °C. The physicochemical properties of parent graphite, as well as the microstructure and physicochemical properties of graphene oxide and resultant graphene were investigated by Raman spectrometer, thermograviment analyzer (TGA), transmission electron microscope (TEM), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FT-IR). Results show that graphene oxide was reduced to graphene with less stack via low-temperature pressure promoted thermal treatment, meanwhile, the degree of disorder reduced: the ratio of ID/IG in Raman spectrum decreases from 0.64 to 0.56. Moreover, graphene derived from low-temperature pressure promoted treatment exhibit better thermal stability than graphene oxide, and oxygen functional groups were removed with a high level. All of results exhibit improved comprehensive properties than graphene synthesized via traditional thermal reduction at 1000 °C.