Recently, researchers from Institute of Solid State physics, Hefei Institutes of Physical Science have found that through co-precipitation method plus plasma spark sintering, low thermal conductivity and excellent thermoelectric performance in copper-antimony alloy can be achieved.
Thermoelectric (TE) technology, which enables direct conversion between heat and electricity, is considered a promising means of sustainable power generation and energy conservation. TE conversion efficiency is defined by a dimensionless value including several parameters in which S is the seebeck coefficient, T is the absolute temperature, ¦Ò is the conductivity, and (L+C) is the total thermal conductivity. These three parameters are interdependent limiting the development of high-performance thermoelectric materials.
However, L can be modulated relatively independently by some typical phonon blocking methods, such as point defects, grain boundaries, lattice strain engineering, dislocations, full-scale graded nano-mesoscopic structures, and endothelial nanostructures embedded in the matrix.
Cu3SbSe4 based materials have attracted wide attention in the range of medium temperature due to its advantages of low cost, ecological friendliness and high element abundance. It can be prepared by top-down methods (such as mechanical alloying (MA), fusion) and bottom-up methods (such as co-precipitation and solvent synthesis). In general, the thermoelectric properties of the resulting compounds depend on the preparation method. However, due to the high thermal conductivity, the peak value (ZT) of the Cu3SbSe4 based system prepared by fusion method is usually less than 1.
Therefore, the team prepared Cu3Sb0.94Sn 0.06Se4-ySy/Cu3SbSe3 nanocomposite in-situ by coprecipitation and spark plasma sintering.
On one hand, the nano-precipitates enhanced the phonon scattering, resulting in its ultra-low thermal conductivity. On the other hand, with the increase of effective mass of the electron density of states, the Seebeck coefficient of the Cu3Sb0.94Sn0.06Se4-ySy/Cu3SbSe3 nano-composite material was improved, and the ZT value was as high as 1.32.
The work was supported by the national natural science foundation of China.
Link to the paper: Ultralow Thermal Conductivity and Extraordinary Thermoelectric Performance Realized in Codoped Cu3SbSe4 by Plasma Spark Sintering
(a) low magnetic field transmission electron microscope image of Cu3Sb0.94Sn0.06Se2.5S1.5 Embedded (a) histogram of size distribution of Cu3SbSe4 based materials;(b-d) HR TEM images of precipitation and matrix. (Image by CHEN Tao)
The temperature dependence of Cu3Sb0.94Sn0.06Se4-ySy(y=0.5, 1, and 1.5) with specific heat; (b) thermal conductivity; (c) lattice thermal conductivity; (d) ZT values (Image by CHEN Tao)