## 4 Conclusions  
Organic-based materials combined with inorganic additives appear to be promising for low-temperature thermoelectric applications. PANI, which exhibits tunable thermoelectric properties and environmental stability, can serve as a very good matrix for the development of organic-based thermoelectric devices. Furthermore, using classic inorganic thermoelectric additives (like Bi\({}_{2}\)Te\({}_{3}\) and its alloys) that display good thermoelectric properties at moderate temperatures is considered to be an effective way to beneficially influence the thermoelectric performance of organic-based thermoelectric devices. For the development of such composites, the investigation of the effect of various processing parameters on the thermoelectric properties is of paramount importance since it allows for the optimization of existing materials and methodologies. In this work, the effects of processing pressure, temperature and time along with the effect of the inorganic additive (BST) content on the thermoelectric properties of PANI-BST composites prepared by simple mechanical mixing were systematically investigated. The most significant experimental parameters influencing them were the inorganic additive content and the processing temperature. More precisely, an increase in the BST content led to an increase in the Seebeck coefficient while having a minor effect on the electrical conductivity and a negligible effect on the thermal conductivity. The processing temperature had a significant effect and increased both the Seebeck coefficient and the electrical conductivity, while there was no noticeable effect on the thermal conductivity. The processing pressure and time employed during pellet formation did not show any direct effect on the  
Figure 9: Graphs of Seebeck coefficient (S), thermal conductivity (\(\kappa\)), electrical conductivity (\(\sigma\)) and figure of merit (ZT) versus measuring temperature (T), within the range of 30–150 \({}^{\circ}\)C (303–423 K), for specimens prepared using the following processing parameters: processing temperature: 80 \({}^{\circ}\)C; processing pressure: 2 tons; processing time: 75 min. The BST content varies from 0 wt.% (green), to 20 wt.% (blue), 30 wt.% (orange), 40 wt.% (grey) and 45 wt.% (yellow). thermoelectric properties. However, the lower pressure allowed for a higher processing temperature and the formation of mechanically stable pellets, which is considered to be an important outcome for the future development of thermoelectric modules. Moreover, BST was proven to be a good candidate as an additive in PANI, resulting in improved thermoelectric performance of the produced composites compared to the pristine polymer matrix. Likewise, the increased processing temperature combined with the appropriate applied pressure improved the thermoelectric performance while retaining the mechanical integrity and stability of the samples. Overall, the presented methodology, involving the simple mechanical mixing of a conductive polymer (PANI) with inorganic additives (BST) under the appropriate processing conditions, can be used in the low-cost, mass-scale manufacturing of thermoelectric composites that could be further exploited in a vast range of applications. Although this cost-effective method can be applied to a wide range of polymers and inorganic thermoelectrics, further improvement is required to achieve better homogenization and dispersion of the inorganic additive within the polymer matrix, which would eventually lead to better thermoelectric performance. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app13179757/s1](https://www.mdpi.com/article/10.3390/app13179757/s1)]([https://www.mdpi.com/article/10.3390/app13179757/s1](https://www.mdpi.com/article/10.3390/app13179757/s1)), Figure S1: Powder XRD of the sample 30-T80-P2-D75 with 30 wt.% BST content. Methodology, S.H. ; investigation, S.H. and P.S.L; formal analysis, S.H. ; validation, S.H. ; writing--original draft, S.H.