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Multiwalled carbon nanotubes have been synthesized by floating reactant method in a vertical tubular reactor. An internal short approach process was developed to achieve the pre-lithiated multiwalled carbon nanotube MWCNTs/graphite composite anodes. Lithium-ion capacitors (LICs) were composed of a pre-lithiated multiwalled carbon nanotubes/graphite composite anode and an activated carbon (AC) cathode. The electrochemical performance of LICs with different MWCNTs content was investigated through galvanostatic charge/discharge and electrochemical impedance. The results show that the charge–discharge performance of LICs was greatly improved with the addition of MWCNTs in anodes. LIC25 (25 wt% MWCNTs) was found to achieve the optimal electrochemical performance. The LIC25 hold a specific capacitance of 58.2 F/g at the current density of 100 mA/g. The maximum energy density and power density were up to 96 Wh/kg and 10.1 kW/kg, respectively, in the current range of 100~8000 mA/g. The continuous galvanostatic charge–discharge cycling tests revealed that the LIC25 maintained excellent capacity retention of 86% after 3000 cycles.

A kind of flexible carbon nanotubes (CNTs) paper was investigated. Cellulose fibers were used as matrix and CNTs were used as conductive additive. The CNT papers were made by suction filtration method. The size and conductivity of the CNT paper can be arbitrarily tailored. The CNT papers show good electrical conductivity, electrochemical and electromagnetic interference (EMI) shielding properties. The electrical conductivity and (EMI) shielding effectiveness (SE) of CNT papers were enhanced with an addition of CNTs in the paper. The electrical conductivity increased from 9.92 S m−1 to 216.3 S m−1 and SE improved from 15 dB to 45 dB with a loading of CNTs from 10 wt% to 71 wt%. The CNT papers also show excellent applications for lithium ion battery, supercapacitors and zinc-manganese batteries. The testing results show that the capacity of supercapacitor reached 46 F/g at a scan rate of 5 mV/s. The reversible discharge capacity reached 474.0 mAh/g with the paper as anode current collector of lithium ion battery. The discharge capacity of Zn–Mn battery increased 100% when CNT paper replaced the graphite collector as current collector.

Pre-lithiated multiwalled carbon nanotube anode was prepared by internal short circuit approach(ISC) for 5[Formula: see text]min, 30[Formula: see text]min, 60[Formula: see text]min and 120[Formula: see text]min respectively. Lithium ion capacitors (LICs) were assembled by using pre-lithiated multiwalled carbon nanotubes as anodes and activated carbon (AC) as cathodes. The structure 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 pristine carbon nanotube electrodes were tested by galvanostatic charge/discharge and electrochemical impedance. The results indicated that pre-lithiation carbon nanotubes greatly improved the charge/discharge performance of LICs. The energy density was four times than conventional electric double-layer capacitors (EDLCs) at the current density of 100[Formula: see text]mA/g. The LICs achieved a specific capacitance of 59.3[Formula: see text]F/g at the current density of 100[Formula: see text]mA/g with 60[Formula: see text]min pre-lithiatiation process. The maximum energy density and power density was 96[Formula: see text]Wh/kg and 4035[Formula: see text]W/kg, respectively. The energy density still remained about 89.0% after 1000 cycles. The LIC showed excellent supercapacitor performance.

In this investigation, multiwalled carbon nanotube (MWCNT) paper consists of MWCNTs and cellulose was fabricated by traditional paper-making method. It was applied directly as negative electrode in flexible lithium ion battery to replace ordinary electrode which is combined with anode material and current collector. The electrochemical performances of the as-produced MWCNT paper (AMP) and carbonized MWCNT paper (CMP) were evaluated in this study. The morphology and structure of the MWCNT papers were observed by scanning electron microscopy (SEM). The electrochemical performance of the battery was operated by cell test and electrochemical impedance spectroscopy (EIS) measurement. The charging and discharging results indicated that the CMP behaves with higher capacity than AMP. And the EIS analysis showed that a lower charge transfer resistance can be obtained in the CMP. The excellent electrochemical performance verifies the feasibility of MWCNT papers as a promising candidate for the anode in flexible lithium ion battery.