Preparation of a Three-Dimensional Ordered Macroporous Carbon Nanotube/Polypyrrole Composite for Supercapacitors and Diffusion Modeling

Abstract

Three-dimensional ordered macroporous (3DOM) carbon nanotube (CNT)/polypyrrole (PPy) composite electrodes for supercapacitor application were prepared through cyclic voltammetric co-polymerization from a solution containing both acid treated CNTs and pyrrole monomers. A self-assembled SiO 2 colloidal crystal was used as the sacrificial template. After electrochemical co-polymerization, the template was removed, and a 3DOM CNT/PPy composite electrode was obtained. The specific capacitance of the composite reached 427 F g -1 at the scanning rate of 5 mV s -1 , and it is calculated that ion diffusion contributed approximate 30 percent to the specific capacitance of the composite. A mathematical model of mass transport was proposed to evaluate the ion diffusion capability on the surfaces of 3DOM, nanoporous and planar films. The calculation results showed that the flux (i.e. ion flux per unit length) of 3DOM film was larger than that of planar film, while the flux of nanoporous film was close to planar film. The model indicates that 3DOM film is favorable for ion transportation, while nanoporous film does the opposite. The model partially explains the reason why the specific capacitance of the prepared 3DOM CNT/PPy composite is far above the specific capacitance values of other reported CNT/PPy composites, even nanoporous CNT/PPy composite.

Super-high rate stretchable polypyrrole-based supercapacitors with excellent cycling stability

“…This is confirmed by the well-defined rectangular shapes of most CVs and the wider working potential windows (Fig. S1) than those in most literatures [36,40,41,[47][48][49][50][51][52]. Fig.…”

“…3a and b, the device can be operated at various scan rates up to 10 V/s and CVs keep the rectangular shape even at a high scan rate of 2 V/s. It should be noted that both numbers are 1-2 orders of magnitude higher than most scan rates for PPy electrodes measured even in aqueous electrolytes [36,40,41,[47][48][49][50][51][52], and are even equivalent to the highest values reported in solidstate the carbon nanotubes-MnO 2 devices, which also keep good rectangular shape at most scan rates [53]. These indicate the PPy-based solid-state supercapacitors fabricated can endure ultrafast voltage/current change rates, which is believed to be a result of effective electrochemical dynamic processes in the supercapacitors.…”

“…The peak at around 1090 cm À 1 corresponds to the mode of in-plane deformation vibration of NH 2 + which forms on the PPy chains via protonation. The bands at 1010 cm À 1 and 940 cm À 1 are attributed to C-H and N-H in-plane ring deformation vibration, and C-C out-of-plane ring deformation vibration [36,48].…”

The impact of morphologies and electrolyte solutions on the supercapacitive behavior for Fe 2 O 3 and the charge storage mechanism

“…Then the Trasatti plots [29,35,36] were used to identify their morphology-dependent capacitance. According to the analysis, the results and the corresponding theoretical specific capacitance of each electrode are given in Fig.…”

Characteristics of a high compressive strength graphite foam prepared from pitches using a PVA–AAc solution

“…Additionally, an increase in the pressure impregnation processing is required for polyurethane foam to compensate for the increased amount of impregnated pitch. However, a hydrogel does not require the pressure impregnation processing to increase the amount of impregnated pitch in the foam and is function of volume shrinkage and pressure during heat treatment, thereby facilitating the fabrication of graphite foams with high compressive strengths [11][12][13][14][15][16][17][18][19][20][21][22][23].…”