Hierarchical porous and N-doped carbon nanotubes derived from polyaniline for electrode materials in supercapacitors

Abstract

Open carbon nanotube materials with hierarchical porosity and N-doping are prepared from polyaniline nanotubes via a combination method of pre-carbonization and post-KOH activation. The morphology, pore texture and surface properties of the carbon materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption, X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The prepared carbon materials have a typical hierarchical pore texture and very high specific surface area up to 3253 m 2 g À1 . The electrochemical capacitive performance of the prepared carbons was systematically investigated in the 6 M KOH electrolyte. HPCT-4 exhibits high charge storage capacity with a specific capacitance of 365.9 F g À1 at a current density of 0.1 A g À1 , good rate capability of 60% in the range of 0.1-10 A g À1 , and excellent stability over 10 000 cycles. The high capacitive performance could be due to the hierarchical porosity combined with high effective surface area and heteroatom doping effects, resulting in both electrochemical double layer and Faradaic capacitance contributions.

Synthesis of activated carbon nanospheres with hierarchical porous structure for high volumetric performance supercapacitors

“…At a high current density of 20 A g -1 , the pristine CNS sample exhibits a specific capacitance of 122 F g -1 , with a retention ratio of 69.7%. After activation, sample CK21 and CK11 show similar capacitance retention ratios of 66.7% (162 F g -1 ) 15 and 72.2% (187 F g -1 ), respectively. While the capacitance retention of CK23 increases to as large as 204 F g -1 , with an obviously improved retention ratio of 77.9%.…”

“…As a result, micropores continue to be generated, but part of the mesopore walls collapse and lead to a minor decrease of the mesopore volume and total pore volume (as shown in Table 1). It is worth mentioning that, the activated samples own moderate pore volumes from 0.735 cm 3 g -1 to 1.143 cm 3 g -1 , which is much lower than previously reported activated porous carbons (from 1.69 cm 3 g -1 to 2.73 cm 3 g -1 ) [13][14][15][16]. The relatively dense structure is quite beneficial for enhancing the volumetric performance in porous carbon electrodes.…”

“…Xu et al synthesized high surface area, hierarchical porous carbons from poly(vinylidene fluoride) by NaOH activation [14]. Zhou et al prepared hierarchical porous and nitrogen-doped carbon nanotubes 4 derived from polyaniline via a combination method of pre-carbonization and post-KOH activation [15]. Zhao et al prepared activated carbon fibers from liquefied wood with controllable porosity [16].…”

Pronounced improvement of supercapacitor capacitance by using redox active electrolyte of p-phenylenediamine

“…In the 2 theta scope of 5 $ 100, there exists one broad and low-intensity XRD diffraction peak. The present peak centered at 24.2 is obviously left-shifted, compared with that of the graphitic carbon materials commonly at 26.4 $ 26.6 [21,22], indicating the predominant existence of amorphous carbon within the matrix of the 700-1:1 sample [23,24]. Besides, the amorphous nature of the 700-1:1 sample was also evinced by the Raman spectrum, as shown in Fig.…”

Effect of unsaturation in bicarboxylic acid dopants for solid‐state synthesis of polyaniline

“…22 , 31 The peaks near 2 ∼ 20 ∘ and 25 ∘ are characteristic of PAni structure attributed to periodicity parallel and perpendicular to the polymer chain, respectively. 32 The intensity near the said two characteristic peaks increases from PO to PM. In the diffractogram of PM, a very sharp peak appears at 2 ∼ 28.5 ∘ , and the corresponding d-spacing of 3.13 Å suggests a different level of compaction of PAni compared to PO and PF.…”