## 3 Results and Discussion
### Physicochemical Characteristics of Samples  
As shown in Figure 5a, the characteristic peaks of PANI at 1572 cm\({}^{-1}\) and 1494 cm\({}^{-1}\) are assigned to the C=C stretching deformation mode of the quinoid and benzenoid rings, respectively. The C-N stretching vibration band at 1303 cm\({}^{-1}\), C=N stretching vibration band at 1146 cm\({}^{-1}\), and O=S=O stretching vibration band at 1034 cm\({}^{-1}\) demonstrate that PANI doped with P-TSA has been successfully prepared in our study [51]. The red line presents the FT-IR spectrum of NCFs. The band at about 3421 cm\({}^{-1}\) is attributed to the N-H stretching vibration, the C-N stretching vibration band and C=N stretching vibration band are still well observed. The spectrum of NCFs corresponds to the disordered carbon-like material with incorporated nitrogen in its structure [31; 33]. The XRD of PANI and NCFs are given in Figure 5b. Two obviously broad peaks at about 20 = 18\({}^{\circ}\), 20\({}^{\circ}\), and 25\({}^{\circ}\) have been ascribed to the (011), (020), and (200) faces of the polymer chain of PANI, respectively. The characteristic peaks at about 20 = 18\({}^{\circ}\), 20\({}^{\circ}\), and 25\({}^{\circ}\) have been ascribed to \(\pi\)-\(\pi\) interchain stacking, the periodicity parallel and perpendicular to the polymer chains [41; 49]. Generally, the dopant P-TSA and polymer undergo various interactions and organize the polymer chains in highly ordered arrangement. The XRD pattern of NCFs exhibit two broad diffraction peaks around 24\({}^{\circ}\) and 43\({}^{\circ}\), which correspond to the (002) and (100) faces of hexagonal graphitic carbon, respectively [2; 4; 31]. The infrared and XRD spectra are similar to those of the carbon materials derived from PANI indicate that the carbonization at 700 \({}^{\circ}\)C for 2 h is suggested for the available conversion of PANI nanofibers to amorphous carbon-like materials. Figure 6a confirms that the nitrogen adsorption-desorption isotherm of NCFs exhibits a mixture of type I isotherm in the low pressure region and type IV isotherm with an H3-typehysteresis loop in the high pressure region, demonstrating the co-existence of micropores and mesopores. This hysteresis loop is indicative of mesoporous adsorbent associated capillary condensation during adsorption-desorption [6]. The Brunauer-Emmett-Teller (BET) surface area, average pore size, and pore volume is 915 m\({}^{2}\) g\({}^{-1}\), 2.7 nm, and 0.61 cm\({}^{3}\) g\({}^{-1}\), respectively. Pore size distribution (inset Figure 6a) verifies that mesopores mainly centre in the region of 2-5 nm, which are more favorable for electrochemical performance [22]. Figure 5: (**a**) FT-IR spectra and (**b**) XRD patterns of samples. As shown in Figure 6b, three X-ray photoelectron spectroscopy (XPS) peaks at a binding energy of 284.9, 400.7, and 532.8 eV correspond to C 1 s, N 1 s, and O 1 s, respectively. The XPS survey spectrum suggests that the nitrogen content and oxygen content are 7.59 at % and 4.98 at %, respectively. The N 1 s high resolution spectrum can be assigned to four peaks: Pyridinic N (N-6), pyrrolic N (N-5), quaternary N (N-Q), and pyridine-N-oxide (N-X) (inset Figure 6b). As shown in Figure 7, the chemical forms of N in nitrogen doped carbon materials have been proposed by research groups [1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14]. N-Q can offer highly active sites, and N-6 and N-5 can improve the wettability of carbon material to increase the effective specific surface area for double layer formation.