Researchers have made significant strides in enhancing the performance of thermoelectric materials, particularly SiGe-based alloys, which are crucial for applications in aerospace exploration. A study led by Runze Shi from the Guangxi Key Laboratory of Information Materials at Guilin University of Electronic Technology has demonstrated a novel approach that simultaneously optimizes the power factor and thermal conductivity of these materials.
The study focused on creating composites of Si80Ge20P1 with cobalt silicide (CoSi2) nanoparticles. By manipulating the amount of CoSi2 in the composite, the researchers were able to leverage the charge transfer effect, which increases carrier concentrations. “The CoSi2 nanoparticles possess higher carrier concentration and smaller work function than the Si80Ge20P1 matrix, pushing up the carrier concentrations of composites,” explained Shi. This increase in carrier concentration is vital for improving the electrical properties of thermoelectric materials.
Moreover, the introduction of nano-sized phase interfaces and stacking faults within the composites enhances the scattering of low-frequency phonons, a critical factor in reducing thermal conductivity. This dual optimization led to impressive results: the team achieved a power factor of 3.41 mW⋅m−1⋅K−2 and a thermal conductivity of 2.29 W⋅m−1⋅K−1, resulting in a dimensionless figure of merit, zT, of up to 1.3 at 873 K in the Si80Ge20P1+0.5% CoSi2 composite.
The implications of this research are significant for the energy sector. Thermoelectric materials convert heat directly into electricity, making them valuable for energy recovery systems, especially in high-temperature environments like aerospace applications. The ability to enhance both the power factor and thermal conductivity could lead to more efficient thermoelectric devices, potentially reducing energy waste and improving energy conversion efficiency.
This research, published in the Journal of Materiomics, offers a promising pathway for developing advanced thermoelectric materials that could revolutionize energy systems in various industries. As the demand for efficient energy solutions grows, innovations like these will be critical in addressing the challenges of energy sustainability and efficiency.