Synthesis and Thermoelectric Properties of TiO2/Cu2SnSe3 Composites

Jiai Ning,Di Wu,Degang Zhao

doi:10.3390/app7101043

Abstract

Thermoelectric (TE) materials are a kind of energy material which can directly convert waste heat into electricity based on TE effects. Ternary Cu2SnSe3 material with diamond-like structure has become one of the potential TE materials due to its low thermal conductivity and adjustable electrical conductivity. In this study, the Cu2SnSe3 powder was prepared by vacuum melting-quenching-annealing-grinding process. The nano-TiO2 particles were introduced into the Cu2SnSe3 matrix by ball milling. Spark plasma sintering (SPS) was employed to fabricate the TiO2/Cu2SnSe3 composites. The X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) were used to study the phase and microstructure of TiO2/Cu2SnSe3 composites. Electrical resistivity, Seebeck coefficient, and thermal conductivity measurement were applied to analyze the thermoelectric properties. For the 1.4%TiO2/Cu2SnSe3 composite, the electrical conductivity was improved whereas the Seebeck coefficient was lower than that of pure Cu2SnSe3. For other TiO2/Cu2SnSe3 samples, the Seebeck coefficient was improved while the electrical conductivity was reduced. The thermal conductivity of TiO2/Cu2SnSe3 composites was lower than that of Cu2SnSe3 matrix, which is attributed to the lower carrier conductivity. A maximum ZT of 0.30 at 700 K for the 1.0%TiO2/Cu2SnSe3 composite was obtained, which was 17% higher than that of the pure Cu2SnSe3 at 700 K.

Highlights

Humans need to care for our “mother earth” with intelligence, diligence, and heart
The X-ray diffraction (XRD) patterns indicate that Cu2 SnSe3 can be synthesized by melting at 1273 K for 12 h and annealing
The distribution of nano-TiO2 in the Cu2 SnSe3 matrix plays an important role in the thermoelectric transport properties

Summary

Introduction

Humans need to care for our “mother earth” with intelligence, diligence, and heart. In a society experiencing an energy shortage, the pursuit of sustainable development has become the social mainstream. The combustion synthesis method can prepare high-performance thermoelectric materials, but it is difficult to precisely control. Many studies report that only Sn location is the best candidate for substituting in the Cu2 Sn(Ge)Se(S) structure, which limits the improvement of TE performance [3,8,10]. Based on those limits mentioned above, the composite was designed on the Cu-based ternary selenides matrix. Li et al reported that the incorporation of a suitable quantity of nanophase PbTe particles into SnSe matrix could efficiently enhance the TE performance of SnSe material [13]. The thermoelectric properties of TiO2 /Cu2 SnSe3 composites were investigated in detail

Materials Synthesis

Results and Discussion

Conclusions