## 3 Results and Discussion
### Thermogravimetric Analysis (TGA)  
The thermal stability of pure ionic liquids (ILs) has been extensively studied in previous papers. For instance, [PERSON] et al. [28] reported an onset decomposition temperature of 435 \({}^{\circ}\)C for [C\({}_{3}\)C\({}_{1}\)Pyrr][TFSI] under similar experimental conditions. Furthermore, the thermogravimetric analysis of binary mixtures performed by several research groups has shown that the addition of lithium salt does not significantly affect the thermal stability of mixtures compared to pure IL [29; 30; 31]. Therefore, the main objective of this part was to evaluate the changes on the thermal stability in the newly formulated binary and ternary mixtures. Figure 3 shows the thermogravimetric (TG) and derivative thermogravimetric (DTG) curves of binary mixtures of [C\({}_{3}\)C\({}_{1}\)Pyrr][TFSI] and ethylene carbonate (EC), with EC molar fractions of 0.3, 0.5, 0.85, and 0.9. Figure 4 presents the TG and DTG curves of the ternary mixtures containing EC and [C\({}_{3}\)C\({}_{1}\)Pyrr][TFSI] (at 0.5 molar fraction) with three different concentrations of LiTFSI. Figure 3: TG/DTG dynamic curves at 10 \({}^{\circ}\)C min\({}^{-1}\) for 0.3:0.7 **(a)**, 0.5:0.5 **(b)**, 0.85:0.15 **(c)**, and [PERSON] **(d)**, molar fractions of EC:[C\({}_{3}\)C\({}_{1}\)Pyrr][TFSI] binary mixtures. Figure 2: DSC curves of [PERSON] mixtures of 0.5 [C\({}_{3}\)C\({}_{1}\)Pyrr][TFSI]0.5 EC and lithium salt concentrations. TG and DTG curves of binary mixtures exhibit two well-defined decomposition steps. An onset temperature of approximately 150 \({}^{\circ}\)C is obtained from TG curves, regardless of the EC molar fraction. Furthermore, it can be seen that the greater the amount of ethylene carbonate (EC) in the binary mixture, the greater the initial mass loss. This mass loss can be attributed to the organic compound EC. [PERSON] et al. [32] stated in their review that the  
Figure 4: TGA/DTG dynamic curves at 10 \({}^{\circ}\)C min\({}^{-1}\) for 0.2 m (**a**), 0.5 m (**b**), and 1 m (**c**), LiTFSI [PERSON] mixtures with EC:[C\({}_{3}\)C\({}_{1}\)Pyrr][TFSI] 0.5:0.5 molar fraction. decomposition temperature of EC is around 250 \({}^{\circ}\)C, but can begin to degrade at 120 \({}^{\circ}\)C in the presence of alkali hydroxides, as is the case here presented. Our findings are in good agreement with [PERSON] et al. [33] who observed a similar behaviour in binary systems consisting of imidazolium- and ammonium-based ionic liquids mixed with EC. They explained that the initial peak suggests that introducing EC into the IL medium strengthens ion-dipole interactions (interactions between different types of molecules) while partially disrupting the weaker dipole-dipole interactions among EC molecules (interactions between similar molecules). As a result, only a portion of the weaker EC-EC interactions are overcome as temperature increases. Notably, the degradation temperature of the EC-IL mixtures is still higher than that of the conventional LiPF\({}_{6}\)/EC-DMC (1:1) electrolyte. The second peak appears at 435 \({}^{\circ}\)C (onset temperature), being also independent of the EC molar fraction, which is in concordance with the results obtained by [PERSON] et al. [28]. These observations provide clear evidence that EC limits the thermal stability of the binary samples. Table 3 shows the characteristic thermogravimetric parameters of the ionic liquid (IL), including \(T_{\text{onset}}\) (representing the beginning of the mass loss process), \(T_{\text{endset}}\) (indicating the end of the mass loss process), \(W_{\text{onset}}\) (mass loss percentage at onset temperature), \(T_{\text{peak}}\) (maximum degradation rate in the DTG curve). Figure 4 and Table 3 show that the initial mass loss remains constant as the amount of lithium salt increases, indicating that lithium addition does not affect the thermal stability of the mixtures compared to the binary ones, following the same trend.