Eco-friendly high-performance silicide thermoelectric materials

Silicide-based thermoelectrics are examples of cost-efficient and environmentally friendly new energy materials, which can be used for power-generation applications in the range of 500-800 K. We review the research focusing on the exploration of n-type Mg2IV-based solid solutions (IV = Si, Ge and Sn) and summarize the most prominent discoveries achieved so far in their studies. Owing to their superior performance compared to other silicides, including p-type Mg2IV, higher manganese silicides (HMS) are commonly considered as a suitable p-type material to be used in thermoelectric modules in conjunction with n-type Mg2IV-based solid solutions for mid-temperature power-generation applications. We describe the strategies used to improve the thermal and electronic transport properties of n-type Mg2IV-based solid solutions and mention some key features of HMS. We also point out the importance of mechanical properties and thermal stability of this family of materials and offer perspectives on the future research work to further improve their performance.