Research Projects

Thermoelectric power generation is a clean and environmentally friendly source of energy, but current materials face challenges such as low energy conversion efficiency, poor durability at high temperatures, high toxicity, high processing costs, and low abundance of raw materials. Oxides are considered viable options due to their better stability and low processing cost. However, achieving high ZT in oxides is challenging. SrTiO3-based perovskites showed maximum ZT (~0.6). Researchers have been able to enhance charge transport in SrTiO3 using aliovalent dopants like Nb and La, but these doped perovskites show higher thermal conductivity (k) than metal-based TE systems like Tellurides. To achieve higher ZT in perovskites, researchers propose designing high-entropy perovskites (HEP) by colonizing the B-site of SrTiO3 with 5 transition metals equiatomically. This could potentially induce multi-phonon scattering, resulting in lower kl. Additionally, HEP structure could be further tailored by A-site doping to exhibit good electrical conductivity and Seebeck coefficient. The proposed work adopts a two-step strategy to enhance thermoelectric performances in HEP. First, machine learning is used to select the A-site and B-site cations of HEP, predicting maximum ZT. Fast sintering technique like SPS is used to synthesize bar-shaped thermoelectric modules from nano-milled oxide precursors. The goal is to develop rare-earth-free, chemically, and thermally stable oxides at high temperatures. All TE properties, including Seebeck coefficient, electrical, and thermal conductivity, will be measured from 300K to 1273K to determine ZT values. Crystal structure and microstructure will be investigated using XRD, FESEM, and TEM.