Spark plasma sintered BaTiO3/graphene composites for thermoelectric applications

Abstract

The global demand for sustainable energy has favored the development of alternative energy conversion technologies, including thermoelectrics. In this regard, thermoelectric oxides are a good alternative to intermetallic alloys (like Bi2Te3 , PbTe ) that contain heavy metals and decompose at high temperatures. Our research on thermoelectrics is focused on spark plasma sintered ceramic matrix/graphene composites. The role of the graphene as a second phase is to increase the electrical conductivity of the system without significantly affecting the thermal conductivity. Spark plasma sintered BaTiO3/graphene composites were prepared with graphene concentrations up to 4% wt. which allowed modifying the DC conductivity between 10-12 and 10-1 S/cm. The composites showed a semiconductor behavior with the resistivity decreasing with increasing temperature. A strong dependence of ZT figure of merit with the graphene concentration and the measurement temperature was found. In this presentation the viability of these composites as environmentally friendly thermoelectrics will be demonstrated.