## 3 Results
While TRGSE exhibits a (001) reflection peak mainly at 13.3 degrees, representing an interlayer distance of 0.67 nm. It seems that both TRGCE and TRGSE have more than one reflection peak. Therefore, the interlayer distance of the composites should depend on the morphology of the intercalated species. To confirm the existence  
Figure 4: (**a**) FTIR (Fourier Transform infrared spectroscopy) spectra of TRG, TRGS, TRGSE, TRGC, and TRGCE; (**b**,**c**) a magnified image for the specific wavenumber region. of more considerable interlayer distances of these composites, SAXS measurements were carried out SAXS probes the repeating microfeatures in a distance range between a few nm to a few tens of nm in polymers or their composites. Figure 6b presents the SAXS patterns obtained from TRG, TRGCE, and TRGSE, which were expressed as scattering intensity vs. \(q\) and corrected for background scattering. The repeating structures of different shapes and sizes can be determined using the scattering vector \(q=\frac{4\pi sin\theta}{\lambda}\) in the equation \(\mathrm{d}=\frac{2\pi}{q}\)[21]. As can be seen in Figure 6b, in the low \(q\) region, the increase in the power law decay exponent represents the scattering of larger-sized objects [21]. For the TRG sample, no specific peak was observed over the whole measured region, implying that no repeating features in the distance range of SAXS were detected. As can be seen, TRGCE showed a scattering peak at \(q\) = 0.25 A\({}^{-1}\), representing an interlayer distance of 2.51 nm, whereas TRGSE exhibited a sharp scattering peak at \(q\) = 0.16 A\({}^{-1}\) indicating an interlayer distance of 3.92 nm. These results indicated that the interlayer distances of both TRGCE and TRGSE are much greater than that of the TRG, suggesting the formation of sizeable ionic aggregation or micelles between the TRG sheets. Figure 5: The thermal gravimetric analysis for the TRG, TRGCE and TRGSE samples. Figure 6: (**a**) X-ray diffraction scattering and (**b**) small angle X-ray scattering of the TRG, TRGCE and TRGSE composites. In this experiment, the asymmetrical structure of a two-electrode EDLC cell (Figure 2) comprised of a TRGSE electrode on one side and TRGCE on the other. Figure 7 shows a Nyquist plot for the TRG, TRGCE and TRGSE cells where the image part of the impedance was plotted against the real part of the impedance. The AC (alternating current) impedance measurement was carried out by applying an AC signal (100 mV) from 1 M Hz to 0.1 Hz. For example, from high to low frequency, the impedance curve of the S\(-\)C\(+\) cell showed a semicircle, followed by a transition zone transferring a vertical line. As can be seen, the semicircle intercepted or approached the real axis at Rs and Rs + Rc. Rs is usually related to the resistance of ion transport in an electrolyte. In a highly-conductive electrolyte, Rc is mainly attributed to electron conduction in the cells, including the contact resistance between conductive composite particles and that between the composite electrodes and the current collectors [22; 23]. The high- to medium-frequency region denotes the ion transfer resistance associated with the porous structure of the electrodes in the S\(-\)C\(+\) cell. Due to the ion diffusion mechanism of the S\(-\)C\(+\) cell between the Warburg diffusion and the ideal capacitive ion diffusion [22; 24], the impedance response deviated from the vertical line to an inclined angle between 45\({}^{\circ}\) and 90\({}^{\circ}\) against the real axis (inset of Figure 7). This non-ideal capacitance response can be attributed to the pore size distribution, which induced a different penetration depth of the S\(-\)C\(+\) cell [24]. The resistance Rp represents the Warburg-related diffusion process in the S\(-\)C\(+\) cell, which can be approximately deduced by extrapolating the low-frequency data to the real axis. The x-axis intercept is, therefore, equal to the internal resistance R = Rs + Rc + Rp [25; 26] (Figure 7, inset). All the samples shared similar Rs values close to 2.8 \(\mathrm{ohm/cm^{2}}\).