Thermoelectric properties of CuO-LiCoO2‑La0.7Sr0.3MnO3 composition materials

Abstract

For the widespread use of thermoelectric materials, it is necessary to reduce their cost, simplify the technology and increase the thermoelectric figure of merit, which is highly dependent on the Seebeck coefficient. Therefore, one of the promising directions is the search for composites for effective thermoelectric converters. In our article, three-component composites consisting of a conductive component of La0.7Sr0.3MnO3, (LSMO), and dielectric components: a mixture of CuO oxides and lithium cobaltite LiCoO2 have been prepared and experimentally investigated as such materials. The phase composition of the obtained samples was studied by X-ray diffraction, electron and optical microscopy. The thermoelectric properties of composite materials have been studied in the field of low temperatures from 30 to 250°C. The best results for Seebeck coefficient 550 μV / K and power factor 0.108 μW / (K2 ∙ m) are shown by experimentally selected compositions containing about 25 % by weight LSMO, 40 % CuO, 30 % LiCoO2, 5 % GeO2. However, the largest value of the power factor (1.859 μW / (K2 ∙ m) was achieved for the sample composition 77 % LSMO, 20 % CuO, 3 % GeO2 with Seebeck 310 μV / K. It should be noted that such three-phase samples have a “p”-type of conductivity. The presence of glass-forming germanium (3 – 5 %) oxide gives samples great mechanical stability.