# Synthesis of Benzoxazine-Based N-Doped Mesoporous Carbons as High-Performance Electrode Materials
## 3 Results and Discussion  
### Microstructure Characterization  
Two different benzoxazine precursors and carbon materials doped with heteroatoms were successfully synthesized. The preparation processes of the materials is illustrated in Figure 1.  
The chemical structure of the BOZ monomer was confirmed using FTIR. The infrared spectrum of aniline-phenol benzoxazine is presented in Figure 2a. The bands at 1598 cm\({}^{-1}\) and 1489 cm\({}^{-1}\) corresponded to the benzene skeleton vibration. The bands at 1369 cm\({}^{-1}\) were assigned to the stretching mode vibration of the C-N-C group from the oxazine ring. The bands at 1226 cm\({}^{-1}\) and 1155 cm\({}^{-1}\) were assigned to the symmetric and the asymmetric stretching mode vibrations of the C-O-C group in the oxazine ring, respectively. The bands at 942 cm\({}^{-1}\) and 750 cm\({}^{-1}\) were vibrations from the oxazine ring and viscous vibration of the benzene ring, respectively. Figure 2b gives the FTIR spectrum of aniline-cardanol benzoxazine, where the bonds at 1600 cm\({}^{-1}\) and 1495 cm\({}^{-1}\) represented the benzene ring skeleton. The bands at 1370 cm\({}^{-1}\) corresponded to the stretching vibration of the C-N-C in the oxazine ring. The bands at 1241 cm \({}^{-1}\) and 1198 cm\({}^{-1}\) were assigned to the symmetric and asymmetric stretching vibration of C-O-C in the oxazine ring, respectively. The peak at 955 cm\({}^{-1}\) was the characteristic absorption peak of the oxazine ring. The peak at 752 cm\({}^{-1}\) was the absorption peak of the outward viscous vibration of the benzene ring. The above characteristic peaks strongly suggested the formation of benzoxazine. The morphology of the carbon materials was characterized using scanning electron microscopy (SEM, Figure 3a-d) and transmission electron microscopy (TEM, Figure 3e,f). Figure 3a-d are SEM images of the carbon materials (NCM-700, NCM-800, NCM-900, and ACNCM-900). The SEM images showed that the obtained N-doped carbon material had a rod-like structure. There were many channels in the rod structure. NCM-900 had a good dispersibility and uniformity due to the complete carbonization and a high nitrogen content. For the TEM images of NCM-900 and ACNCM-900 (Figure 3e,f), NCM-900 (Figure 3e) showed a more regular fringe arrangement than ACNCM-900 (Figure 3f). Within a certain range, as the nitrogen content increased, the porosity of the nitrogen-doped porous material also increased [31]. Figure 1: The preparation process for N-doped carbons using benzoxazine as precursor. BOZ: benzoxazine, HF: hydrofluoric acid. Figure 2: The FTIR of (**a**) aniline-phenol type benzoxazine and (**b**) aniline-cardanol type benzoxazine. The elemental compositions and nitrogen chemical states in NCM-900 and ACNCM-900 were characterized using X-ray photoelectron spectroscopy (XPS), as shown in Figure 4. The N 1s spectra of NCM-900 could be split into three peaks, corresponding to pyridinic N (397.5 eV), pyrrolic N (399.3 eV), and quaternary N (400.7 eV) (Figure 4a). The N 1s peaks of ACNCM-900 are shown in Figure 4b. It exhibited the same three nitrogen functional groups, centering at 398.1 eV, 399.3 eV, and 400.6 eV, which were also assigned to pyridinic N, pyrrolic N, and quaternary N, respectively [32]. In previous research, pyridinic N and pyrrolic N have been shown to have a positive effect at improving capacitive performance via pseudo-capacitance contribution due to configuration effects of separate electron pairs. Furthermore, the introduction of quaternary N could also facilitate electron transfer and enhance the conductivity of carbon materials [33; 34; 35; 36; 37]. The XPS peak analysis results of the two carbon materials are summarized in Table 1.  
Small angle X-ray diffraction and wide-angle XRD were used to determine the structure of the produced carbon materials (NCM-700, NCM-800, NCM-900, and ACNCM-900) and SBA-15. The XRD patterns are presented in Figure 5a,b.