• Energy Research

The power factor of GeSe enhanced and thermal conductivity decreased by Te substitution and thereby, GeSe0.80Te0.20 exhibits high ZT.

The power factor of GeSe enhanced and thermal conductivity decreased by Te substitution and thereby, GeSe0.80Te0.20 exhibits high ZT.

As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe1−xLiIx (x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe)0.98(LiI)0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe)x(LiSbTe2)2 compounds that were reported earlier.

As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe1−xLiIx (x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe)0.98(LiI)0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe)x(LiSbTe2)2 compounds that were reported earlier.

A novel and faster synthesis method, which combines ball milling, and microwave radiation, has been successfully adopted to produce CuFe2S3 isocubanite with thermoelectric properties comparable to that prepared by a conventional melt-processing route.

A novel and faster synthesis method, which combines ball milling, and microwave radiation, has been successfully adopted to produce CuFe2S3 isocubanite with thermoelectric properties comparable to that prepared by a conventional melt-processing route.

This research reports, for the first time, the combination of food-grade coconut oil and coconut shell-based activated carbon as precursors for the synthesis of bio-based shape-stabilized phase change materials (bioSSPCM). Despite its low melting enthalpy, simple physical blending by heating and mixing is found to be a very reliable preparation method for the completely coconut-based materials, producing a thermally stable bioSSPCM with anti-leakage. No difference between food grade and analytical grade coconut oil, in terms of its application for SSPCMs, was evident. Further, comparing the performance of coconut oil against octadecane, a conventional phase change material, it was found that with the same synthesis conditions, the coconut oil exhibited improved stability, with less leakage after phase change cycling.