## 3 Results and Discussion
### Electrochemical Performance
The possible reason is a sharp decay of the cycle life of the electrode material, as that the electrolyte has a large irreversible capacity during multiple charge and discharge processes, and the embedding of solvent molecules directly leads to the serious collapse of the electrode material. Figure 3: Time curves of (**a**) PANI, (**b**) PANI @ CQDs, (**c**) PANI @ FMWCNTs and (**d**) FMWCNTs @ CQDs @ PANI constant current charge and discharge cycle for 20 periods. To further compare the electrochemical capacitive behaviors of PANI, PANI @ CQDs, PANI @ FMWCNTs and FMWCNTs @ CQDs @ PANI electrodes, CV tests were carried out at 10 mv\(\cdot\)s\({}^{-1}\), as shown in Figure 5. It can be seen from the figure that there is a significant redox peak in the FMWCNTs @ CQDs @ PANI curve in the interval of 0.4-0.5 V, indicating that the redox reaction is reversible. It can also be observed that the cyclic voltammetry curve is approximately embodied as an isosceles triangle, which reflects the combination of the electric double layer capacitance and the tantalum capacitance of the composite material, good reversibility [32; 36]. It is also obvious that  
Figure 4: Retention rates of PANI, PANI @ CQDs, PANI @ FMWCNTs and FMWCNTs @ CQDs @ PANI under different number of cycles. Figure 5: Cyclic voltammetry curves of PANI, PANI @ CQDs, PANI @ FMWCNTs and FMWCNTs @ CQDs @ PANI. FMWCNTs @ CQDs @ PANI electrode has much higher redox peak current, suggesting increased specific capacitance. There is also a significant redox peak in the PANI @ CQDs and PANI @ FMWCNTs cyclic voltammetry curve. The two types of electrodes show the same pair of redox peaks, which are attributed to redox transition of PANI between CQDs and FMWCNTs [37]. In comparison, the redox peak in the pure PANI is very weak [38], indicating that the redox reaction is less reversible. Combined with the conclusions obtained in Figure 2, the electrical activity and reversibility of the PANI @ FMWCNTs electrode in the early stage are better than those in the later stage. In addition, from the active area of the curve, the electrical activity of the ternary active material is better than the composite materials PANI @ CQDs and PANI @ FMWCNTs, as well as pure polyaniline, with strong energy storage capacity [32]. Furthermore, it shows that the compounding of three active materials has been successful. Therefore, the conclusion about the specific capacitance obtained in the constant current charge and discharge curve of Figure 2 was verified: ternary active electrode > binary active electrode > pure polyaniline. Figure 6 shows the cyclic voltammetric curves of PANI, PANI @ CQDs, PANI @ FMWCNTs and FMWCNTs @ CQDs @ PANI at a series of scanning rate ranging from 5 to 50 mv\(\cdot\)s\({}^{-1}\). It can be seen that: (I) the specific capacitance decreases with the increase in scanning rate (Table 1), which may be due to the superior charge mobilization per unit time [39]; (II) the response current increases with the increase in scanning rate, which shows that the composite has good electrochemical reversibility and high-power characteristics [32]. Figure 6: CV curves at different scan rates of (**A**) pure PANI, (**B**) PANI @ CQDs, (**C**) PANI @ FMWCNTs, and (**D**) FMWCNTs @ CQDs @ PANI.