Numerical simulation and experimental validation of laser 3D printing randomly porous thermoelectric materials Bi_0.5Sb_1.5Te₃

Porous thermoelectric (TE) materials are of significant importance as they can effectively reduce thermal conductivity by modulating phonon transport while maintaining relatively good electrical properties, thereby enhancing TE energy conversion efficiency. This work establishes a two-dimensional finite element model based on the microstructural characteristics of randomly porous TE materials to simulate their TE transport properties. Using 3D-printed randomly porous P-type bismuth telluride (Bi_0.5Sb_1.5Te₃) materials as the research object, representative two-dimensional randomly porous geometric models were abstracted from scanning electron microscopy (SEM) images. Simulations were conducted focusing on two structures with porosities of 45.6% and 54.5%, respectively. The temperature-dependent trends of the Seebeck coefficient, electrical conductivity, thermal conductivity, and TE figure of merit (ZT value) were obtained through proposed finite element calculations. The simulation results were compared with experimental measurements at the same porosity levels, thereby validating the model's effectiveness. Furthermore, the study systematically analyzed the relationship between the TE figure of merit ZT and extended porosity, revealing the comprehensive influence mechanism of porous structures on TE performance. This research provides a theoretical basis and numerical analysis approach for optimizing the performance of porous TE materials through microstructural design.