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Multiwalled carbon nanotubes(MWCNTs) were fluorinated to get the material of MWCNTs fluoride with different atomic ratio. The ratio of fluorine and carbon was 0.28(CF0.28), 0.56(CF0.56) and 0.78(CF0.78) respectively. The fluoride MWCNTs were used as cathode active material to coat on aluminum foil, lithium metal foil as counter electrode in Li/CFx batteries. The structures and properties were characterized by thermal gravimetric analyzer(TGA), scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS). The electrochemical performance was tested by galvanostatic discharge test. The results show that the battery with CF0.78 has the best electrochemical performance. At the current density of 39mA/g, the battery displays high discharge specific capacity of 724mAh/g and appears with a more stable platform for the discharge process. At the current discharge rate of 0.05C, the utilization of three kinds of MWCNTs fluoride electrodes is 73.4%, 89.6%, 92.9%. When the discharge rate is 2C, batteries with three different MWCNTs fluoride have discharge specific capacity attenuation rate of 68.8%, 34.1%, and 39.6%. It indicates that the discharge specific capacity attenuation rate can be mitigated to a certain extent with the improved level of fluoridation. Although the discharge capacity attenuation rate of CF0.78 is higher than that of CF0.56, CF0.78 has the most stable discharge curve at the same discharge rate.

Pre-lithiated multiwalled carbon nanotube anode was prepared by internal short approach(IS) for 5min, 30min and 60min. Lithium ion capacitors (LICs) were assembled using pre-lithiated multiwalled carbon nanotubes as cathode and activated carbon(AC) as anode. The structure characterization of multiwalled carbon nanotubes and electrodes were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performance of pre-lithiated multiwalled carbon nanotube electrodes and pure multiwalled carbon nanotubes electrodes were tested by galvanostatic charge/discharge and electrochemical impedance spectrum. The electrochemical tests indicate that the charge-discharge performance of LIC is greatly improved by pre-lithiation of multiwalled carbon nanotubes. The energy density reaches about 4 times over conventional electric double-layer capacitors (EDLCs) at the current density of 100mA/g. The LICs achived a specific capacitance of 57F/g at the current density of 100mA/g with 60min pre-lithiatiation process. The maximum energy density and power density reach 90Wh/kg and 4130W/kg respectively in the current range of 100-3200mA/g. The capacity retention rate remains more than 85% after 1000 cycles. The LIC shows excellent supercapacitor performance.

Whisker multiwalled carbon nanotubes (WMWCNTs) and multiwalled carbon nanotubes (MWCNTs) were synthesized via chemical vapor deposition (CVD), and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Raman spectroscopy. Paper fibers were used as matrix material, WMWCNTs and MWCNTs as functional material. Paper fibers were mixed with dispersed WMWCNTs and MWCNTs by speed-cutting procedure in water. Then the composite papers were fabricated by vacuum filtration method. The electrochemical performance of the supercapacitor was tested by cyclic voltammetry, galvanostatic charge/discharge. The testing results indicate the supercapacitor has a maximum capacitance of 120F/g at a scan rate of 1mV/s and has a specific capacitance of 51.5F/g at 0.4A/g. The maximum energy density and power density reach 63.7Wh/kg and 3.99kW/kg respectively in the current range of 0.4-1.4A/g.

Nano silicon and multiwalled carbon nanotubes(MWCNTs) composites were used as active materials, paper fiber as substrate, MWCNTs as conductive agent, MWCNTs conductive paper was obtained to replace the copper foil current collector and applied in silicon based lithium ion battery. The morphology and the electrochemical performance of the composites were analyzed by scanning electron microscopy (SEM),transmission electron microscopy(TEM), galvanostatic charge-discharge tests and electrochemical impedance spectroscopy(EIS) tests. The results indicate that the lithium ion battery with MWCNTS paper/nano silicon composites reaches a specific capacity of about 1000mAh/g after 50 cycles in the current density of 80mA/g, and has good cycle stability even in the high current density of 2000mA/g.