Repairable Characteristic of Zn₄Sb₃ and Its Influence on Thermoelectric Performance

Abstract

Thermoelectric materials inevitably experience performance degradation and lose their value after a long period of use. A means of repairing damaged thermoelectric materials would help extend their service life. Zn 4 Sb 3 is a promising thermoelectric material at medium temperatures, but its stability is controversial. We observed that Zn 4 Sb 3 partially decomposed into ZnSb and Zn after heat treatment at 523 K for 5 h. Zn ions migrated to the grain boundaries and precipitated as metallic Zn. The removal of Zn caused a large amount of nano-ZnSb to appear in the crystal grains. The scattering of phonons by nano-ZnSb and metallic Zn improved the thermoelectric performance of the Zn 4 Sb 3 composites. After a further 5 h of heat treatment at a higher temperature of 623 K, the partially decomposed Zn 4 Sb 3 returned to its undecomposed state. Both nano-ZnSb and metallic Zn disappeared, and the Zn 4 Sb 3 sample recovered from a multiphase to a single-phase system. The thermoelectric performance was almost the same as before the heat treatment. Molecular dynamics simulations revealed that this repairability originates from the reversible migration of Zn. The increased potential energy powers the lattice contraction, and the force driving the lattice contraction also drives the reverse migration of Zn. The high diffusion rate of Zn(2) atoms shortens the repair process. This repairable feature of Zn 4 Sb 3 allows it to switch flexibly between performance and stability. The reversible migration of Zn gives Zn 4 Sb 3 the potential to be used in a solid-state battery.

Effects of stresses on the thermoelectric properties of In4Se3

“…The global focus on energy has driven extensive research into thermoelectric materials with the ability to directly convert waste heat into electricity. [1][2][3][4] These materials' thermoelectric properties are determined by the dimensionless thermoelectric figure of merit, ZT. This value is calculated using the formula ZT = S 2 sT/(k L + k e ), where S, s, T, k L , and k e represent the Seebeck coefficient, electrical conductivity, absolute temperature, and lattice and electronic thermal conductivity, respectively.…”

Impurity Removal Leading to High-Performance CoSb3-Based Skutterudites with Synergistic Carrier Concentration Optimization and Thermal Conductivity Reduction

“…Thermoelectric materials, such as room-temperature Bi 2 Te 3 , 9 mid-temperature tellurides, 10 silicides, 11 zinc−antimony alloy, 12 half-Heusler, 13 lead antimony silver telluride (LAST), 14 and high-temperature SiGe, 15 have been widely studied. Among them, CoSb 3 -based skutterudites have high carrier mobility (μ) and S, as well as high thermal stability.…”

“…Thermoelectric materials, such as room-temperature Bi 2 Te 3 , mid-temperature tellurides, silicides, zinc–antimony alloy, half-Heusler, lead antimony silver telluride (LAST), and high-temperature SiGe, have been widely studied. Among them, CoSb 3 -based skutterudites have high carrier mobility (μ) and S , as well as high thermal stability. , Intrinsic CoSb 3 has a cage-like crystal structure with two voids occupying the 2a sites, (0, 0, 0) and (1/2, 1/2, 1/2), in its primitive cell, which can be filled by atoms with smaller atomic radii, such as alkaline-earth atoms, , rare-earth atoms, , and alkaline metals. , These fillers can tune the carrier transport properties of CoSb 3 into n-type or p-type.…”