Assessment of thermoelectric, mechanical, and microstructural reinforcement properties of graphene-mixed heterostructures

Abstract

We examine the role of graphene nanoplates (GNPs) in the critical properties of thermoelectric GNP nanocomposites. After a detailed analysis of the thermoelectric, microstructural, and mechanical characteristics of such nanocomposites, we present a case study based on CoVSn-GNP heterostructures. It is shown that GNPs can improve the mechanical properties without deteriorating the thermoelectric properties of the material. CoVSn-GNP bulk composites are fabricated using powder metallurgy and spark plasma sintering with a GNP weight percentage range of 0–1. All samples with the addition of GNPs showed improved mechanical properties compared with pristine CoVSn. The sample with 0.5 wt % GNPs showed the highest value of Vickers Hardness (737 HV) among all of the studied compositions. Moreover, the fracture toughness was higher for the samples with a lower average crystal size. The concentration and dispersion of GNPs did not significantly change the CoVSn multiphase microstructure; however, it influenced the thermoelectric factors by reducing the thermal conductivity and increasing the Seebeck coefficient, leading to the enhancement of the thermoelectric figure of merit.