P-type thermoelectric material with high Z value
Leizig Technologies of Thermoelectric devote to research and produce high performance thermoelectric material and related products to recycle heat from industrial and solar energy.
We have acquired quinary P-type thermoelectric material with high ZT independently. In our simple batch production, this alloy has Z=α2σ/κ ranged between 5.89×10-3 and 3.43×10-3K-1 from 300K to 400K which means a average Z value 4.49×10-3 K-1 . The average electric conductivity σ is 4.51×104 S·m-1 and the density is 6.8g·cm-1. The Seebeck coefficient is 221μV·K-1 to 240μV·K-1 between 300K and 400K. Nevertheless, the thermal conductivity κ=κe+κl is as low as 0.4962 W/m·K to 0.6499 W/m·K from 325K to 400K about 50% lower than current commercial material dramatically improved ZT value to 1.81 at 325K. The cooling efficiency will be 30% higher than current commercial Peltier cooling devices.
Seebeck coefficient of our P-type alloy perpendicular to axis C which is cleavage plane is 330μV·K-1 and parallel to axis C is 180μV·K-1. The P-type thermoelectric ingot is grown with the alloy of Bi, Sb, Te, Se and S. The atomic radius of S is much smaller than the Bi, Sb and Te which effect dense lattice distortion and induce large number of point-defects in lattice. Those point-defects can effectively scatter phonons, leading to a much lower lattice thermal conductivity. As Se and S have bigger electronegativity than Te, They will replace Te in lattice and form isoelectronic trap in material. The isoelectronic traps will trap electron from energy band leading to electronic bound state which maintain a higher Seebeck coefficient than ternary alloy. The Z value will be near 90% of theory value 5.31×10-3 K-1 if we improve our equipment and perfect production technique. We have applied for invention patent about this P-type material in the domestic and international. Violators will be prosecuted.（Patent NO. 201510579429.5 ; 14935452.）