Interface Layer of Te-based Thermoelectric Device: Abnormal Growth and Interface Stability

doi:10.15541/jim20240057

Abstract

Abstract:

Though Te has excellent figure of merit (ZT), the severe element diffusion and reaction at the Te/metallic-electrodes interface render high contact resistivity (ρ_c) and low device conversion efficiency (η). Therefore, it is critical to develop suitable barrier layers for optimizing the bonding between Te and metallic electrodes. In this work, an appropriate barrier layer, NiTe_2-_m (Ni_xTe (x=0.500~0.908)), was screened based on gradient structure. No reaction layers and defects at the interface of Ni_0.5Te/Te_0.985Sb_0.015/Ni_0.5Te were detected before and after aging at 473 K. Low ρ_c (less than 10 μΩ·cm²) and high η (about 75% of the theoretical value under a temperature difference of 180 K (hot end: 473 K)) were achieved and maintained stable during aging, showing excellent thermal stability of the interface. When x>0.500, the thickness of the interface reaction layer decreased with x increasing, showing the retarding effect dominating the growth behavior of interface reaction layer not from the usual thermodynamic factors, such as interface reaction energy and composition gradient, but from the “atom vacancy” on formation of the reaction layer.

Key words: Te, thermoelectric device, diffusion dynamic, barrier, thermal stability

CLC Number:

TN377

MIAO Xin, YAN Shiqiang, WEI Jindou, WU Chao, FAN Wenhao, CHEN Shaoping. Interface Layer of Te-based Thermoelectric Device: Abnormal Growth and Interface Stability[J]. Journal of Inorganic Materials, 2024, 39(8): 903-910.

Figures/Tables 17

Fig. 1 Microstructure and composition of Te0.985Sb0.015 precursor powder (a) Backscattered SEM image; (b) XRD patterns and quasi-1D chain crystal structure of Te and Te0.985Sb0.015 powders; Colorful figures are available on website

Fig. 2 Composition and lattice parameters of NixTe samples (a) XRD patterns; (b) Lattice constant a changed with x

Fig. 3 (a) Thicknesses of the interface reaction layers (IRLs) at the Te0.985Sb0.015/NixTe interfaces, and (b) formation Gibbs free energies in molar (ΔrGT) of the interface products at the Te0.985Sb0.015/NixTe interfaces

Fig. 4 Diagram of the growth of the interface reaction layer (IRL) at Te/NiTe2-m interface

Table 1 Total migration of atoms (CN·l) at Te0.985Sb0.015/NixTe interface

Total migration of atoms	x=0.500	x=0.563	x=0.667	x=0.833	x=0.908	Te_0.985Sb_0.015/Ni
C_N·l/(mol·cm^-2)	0	0.1297	0.2134	0.2810	0.3154	0.5653

Fig. 5 Microstructures of Te0.985Sb0.015/NixTe interfaces after aging at 473 K for 6 and 12 d Backscattering SEM images for (a) x=0.500, (b) x=0.563, and (c) x=0.667

Fig. 6 Performance of NixTe/Te0.985Sb0.015/NixTe (x=0.500, 0.563, 0.667) single-leg devices (a, b) Room temperature V-I curves and contact resistivity, ρc, before aging; (c) Time-dependent room temperature ρc; (d) Time-dependent efficiency, η, under a temperature difference of 180 K (hot end: 473 K, cold end: 293 K)

Fig. S1 Fracture microstructure and element distribution of sintered Te0.985Sb0.015 (a, b) Backscattered SEM images; (c) Corresponding EDS mapping

Fig. S2 Thermoelectric performance of Te0.985Sb0.015 in the direction parallel to the sintering pressure (a) Total thermal conductivity, κ; (b) Carrier concentration, n; (c) Resistivity; (d) Seebeck coefficient; (e) Power factor, PF; (f) Dimensionless ZT of Te0.985Sb0.015; The test results of Pei et al.[15] are also drawn in the figures for comparison

Fig. S3 Electrical performance of NixTe samples (a) Resistivity; (b) Seebeck coefficient

Fig. S4 Microstructures and element distributions of sintered Te0.985Sb0.015/NixTe interfaces Backscatter SEM images and EDS spectra for (a) x=0.500, (b) x=0.563, (c) x=0.667, (d) x=0.833, and (e) x=0.908

Fig. S5 Backscatter SEM image of sintered Te0.985Sb0.015/Ni interface

Table S1 Thermodynamic data. Values of entropy (ST), enthalpy (HT), and Gibbs free energy (GT) at 298.15, 600.00 and 700.00 K, respectively

Phase lable	Formula in reference	Formula used here	Temperature/K	S_T/(J·mol^-1·K^-1)	H_T/(kJ·mol^-1)	G_T/(kJ·mol^-1)	Ref.
δ(-NiTe_2-_x, 52.2%-66.7% (in atom) Te)	Ni_0.476Te_0.524	Ni_0.908Te	298.15	76.393	-51.908	-74.685	[40]
			600.00	112.729	-36.120	-103.758
			700.00	121.397	-30.494	-115.472
	Ni_0.4Te_0.6	Ni_0.667Te	298.15	66.917	-47.833	-67.785	[40]
			600.00	98.732	-33.987	-93.226
			700.00	106.415	-29.000	-103.491
	Ni_0.333Te_0.667	Ni_0.5Te	298.15	60.135	-43.778	-61.707	[40]
			600.00	88.253	-31.552	-84.504
			700.00	95.001	-27.172	-93.673
Te	Te	Te	298.15	49.497	0.000	-14.757	[41]
			600.00	69.537	8.766	-32.956
			700.00	74.694	12.114	-40.171
Ni	Ni	Ni	298.15	29.874	0.000	-8.907	[41]
			600.00	50.419	9.008	-21.243
			700.00	55.546	12.326	-26.557

Table S2 Molar formation Gibbs free energies (ΔrGT) of interface products at 298.15, 600.00 and 700.00 K, respectively

Chemical reaction equation	Temperature/K	Δ_rS_T/(J·mol^-1·K^-1)	Δ_rH_T/(kJ·mol^-1)	Δ_rG_T/(kJ·mol^-1)
0.25Te+0.75Ni_0.667Te→Ni_0.5Te	298.15	-2.427	-7.903	-7.180
	600.00	-3.180	-8.253	-6.345
	700.00	-3.484	-8.451	-6.012
0.449Te+0.551Ni_0.908Te→Ni_0.5Te	298.15	-4.182	-15.177	-13.930
	600.00	-5.083	-15.586	-12.536
	700.00	-5.426	-15.809	-12.010
1.5Ni+Te→Ni_1.5Te	298.15	5.692	-57.500	-59.197
	600.00	5.969	-57.318	-60.899
	700.00	8.110	-56.023	-61.700

Table S3 Density (ρ), molar mass (M) and moles of the bound Te per mole substance

Item	NiTe₂ (Ni_0.5Te)	NiTe_1.776 (Ni_0.563Te)	NiTe_1.5 (Ni_0.667Te)	NiTe_1.2 (Ni_0.833Te)	NiTe_1.1 (Ni_0.908Te)	Ni	Te	NiTe_0.667 (Ni_1.5Te)
M/(g·mol^-1)	313.893	285.311	250.093	211.813	199.053	58.693	127.600	143.802
n	2.000	1.776	1.500	1.200	1.100	0.000	-	0.667
ρ/(g·cm^-3)	7.701	7.565	7.363	7.086	6.976	8.910	-	8.126

Fig. S6 Performance of Ni0.5Te/Te0.985Sb0.015/Ni0.5Te single-leg devices under a temperature difference of 180 K (Hot end: 473 K, Cold end: 293 K) (a) Current-dependent output voltage, Uout; (b) Current-dependent heat flux, Q

Fig. S7 Aging-time dependent performance of Ni0.5Te/Te0.985Sb0.015/Ni0.5Te single-leg devices under a temperature difference of 180 K (Hot end: 473 K, Cold end: 293 K) (a, c) Current-dependent output voltages, Uout and (b, d) current-dependent heat flux, Q, after aging for (a, b) 3 and (c, d) 6-15 d; Aging-time dependent (e) open-circuit voltage, Uo and (f) internal resistance, Rin with inset in (f) showing internal resistivity, R, of the devices

References 43

[1]	WEI J, YANG L, MA Z, et al. Review of current high-ZT thermoelectric materials. Journal of Materials Science, 2020, 55(27): 12642.
[2]	LIU H T, SUN Q, ZHONG Y, et al. Enhanced thermoelectric performance of n-type Nb-doped PbTe by compensating resonant level and inducing atomic disorder. Materials Today Physics, 2022, 24: 100677.
[3]	SU L, WANG D, WANG S, et al. High thermoelectric performance realized through manipulating layered phonon-electron decoupling. Science, 2022, 375(6587): 1385.
[4]	SUN J, WANG R, CUI W, et al. Percolation process-mediated rich defects in hole-doped PbSe with enhanced thermoelectric performance. Chemistry of Materials, 2022, 34(14): 6450.
[5]	AN D, WANG J, ZHANG J, et al. Retarding Ostwald ripening through Gibbs adsorption and interfacial complexions leads to high-performance SnTe thermoelectrics. Energy & Environmental Science, 2021, 14(10): 5469.
[6]	YANG J, LI G, ZHU H, et al. Next-generation thermoelectric cooling modules based on high-performance Mg₃(Bi,Sb)₂ material. Joule, 2022, 6(1): 193.
[7]	CHU J, HUANG J, LIU R, et al. Electrode interface optimization advances conversion efficiency and stability of thermoelectric devices. Nature Communications, 2020, 11(1): 2723.
[8]	BJØRK R. The universal influence of contact resistance on the efficiency of a thermoelectric generator. Journal of Electronic Materials, 2015, 44(8): 2869.
[9]	ZHANG Q H, BAI S Q, CHEN L D. Technologies and applications of thermoelectric devices: current status, challenges and prospects. Journal of Inorganic Materials, 2019, 34(3): 279.
[10]	WU X, HAN Z, ZHU Y, et al. A general design strategy for thermoelectric interface materials in n-type Mg₃Sb_1.5Bi_0.5 single leg used in TEGs. Acta Materialia, 2022, 226: 117616.
[11]	HU X K, ZHANG S M, ZHAO F, et al. Thermoelectric device: contact interface and interface materials. Journal of Inorganic Materials, 2019, 34(3): 269.
[12]	SAKANO M, HIRAYAMA M, TAKAHASHI T, et al. Radial spin texture in elemental tellurium with chiral crystal structure. Physical Review Letters, 2020, 124(13): 136404.
[13]	REITZ J R. Electronic band structure of selenium and tellurium. Physical Review, 1957, 105(4): 1233.
[14]	李蓉, 陈少平, 樊文浩, 等. 孤对电子对碲热电传输性能的影响. 材料导报, 2018, 32(21): 3726.
[15]	LIN S Q, LI W, ZHANG X Y, et al. Sb induces both doping and precipitation for improving the thermoelectric performance of elemental Te. Inorganic Chemistry Frontiers, 2017, 4(6): 1066.
[16]	RAO F, DING K, ZHOU Y, et al. Reducing the stochasticity of crystal nucleation to enable subnanosecond memory writing. Science, 2017, 358(6369): 1423.
[17]	GUO J, FAN W, WANG Y, et al. Study on improving comprehensive property of Te-based thermoelectric joint. Journal of Alloys and Compounds, 2021, 886: 161242.
[18]	郭敬云, 陈少平, 樊文浩, 等. 改善Te基热电材料与复合电极界面性能. 物理学报, 2020, 69(14): 179.
[19]	HE Z, CHANG L G, LIN Y, et al. Real-time visualization of solid-phase ion migration kinetics on nanowire monolayer. Journal of the American Chemical Society, 2020, 142(17): 7968.
[20]	TASHIRO M, SUKENAGA S, IKEMOTO K, et al. Interfacial reactions between pure Cu, Ni, and Ni-Cu alloys and p-type Bi₂Te₃ bulk thermoelectric material. Journal of Materials Science, 2021, 56(29): 16545.
[21]	FERRERES X R, AMINORROAYA YAMINI S, NANCARROW M, et al. One-step bonding of Ni electrode to n-type PbTe—a step towards fabrication of thermoelectric generators. Materials & Design, 2016, 107: 90.
[22]	ZHANG J, WEI P, ZHANG H, et al. Enhanced contact performance and thermal tolerance of Ni/Bi₂Te₃ joints for Bi₂Te₃-based thermoelectric devices. ACS Applied Materials & Interfaces, 2023, 15(18): 22705.
[23]	CHEN J, FAN W, WANG Y, et al. Improvement of stability in a Mg₂Si-based thermoelectric single-leg device via Mg₅₀Si₁₅Ni₅₀ barrier. Journal of Alloys and Compounds, 2022, 926: 166888.
[24]	WANG Y, CHEN J, JIANG Y, et al. Suppression of interfacial diffusion in Mg₃Sb₂ thermoelectric materials through an Mg_4.3Sb₃Ni/Mg_3.2Sb₂Y_0.05/Mg_4.3Sb₃Ni-graded structure. ACS Applied Materials & Interfaces, 2022, 14(29): 33419.
[25]	CHEN S, CHEN J, FAN W, et al. Improvement of contact and bonding performance of Mg₂Si/Mg₂SiNi₃ thermoelectric joints by optimizing the concentration gradient of Mg. Journal of Electronic Materials, 2022, 51(5): 2256.
[26]	SUN Y, YIN L, ZHANG Z, et al. Low contact resistivity and excellent thermal stability of p-type YbMg_0.8Zn_1.2Sb₂/Fe-Sb junction for thermoelectric applications. Acta Materialia, 2022, 235: 118066.
[27]	SUN Z, CHEN X, ZHANG J, et al. Achieving reliable CoSb₃ based thermoelectric joints with low contact resistivity using a high-entropy alloy diffusion barrier layer. Journal of Materiomics, 2022, 8(4): 882.
[28]	ARVHULT C M, GUÉNEAU C, GOSSÉ S, et al. Thermodynamic assessment of the Ni-Te system. Journal of Materials Science, 2019, 54(16): 11304.
[29]	LIAO C N, LEE C H, CHEN W J. Effect of interfacial compound formation on contact resistivity of soldered junctions between bismuth telluride-based thermoelements and copper. Electrochemical and Solid-State Letters, 2007, 10(9): 23.
[30]	XIA H, CHEN C L, DRYMIOTIS F, et al. Interfacial reaction between Nb foil and n-type PbTe thermoelectric materials during thermoelectric contact fabrication. Journal of Electronic Materials, 2014, 43(11): 4064.
[31]	LI C C, DRYMIOTIS F, LIAO L L, et al. Interfacial reactions between PbTe-based thermoelectric materials and Cu and Ag bonding materials. Journal of Materials Chemistry C, 2015, 3(40): 10590.
[32]	WANG X, GU M, LIAO J C, et al. High temperature interfacial stability of Fe/Bi_0.5Sb_1.5Te₃ thermoelectric elements. Journal of Inorganic Materials, 2021, 36(2): 197.
[33]	TSUTOMU K, HIROMASA T, SATO H K, et al. Enhancement of average thermoelectric figure of merit by increasing the grain-size of Mg_3.2Sb_1.5Bi_0.49Te_0.01. Applied Physics Letters, 2018, 112(3): 33903.
[34]	AN D, CHEN S, LU Z, et al. Low thermal conductivity and optimized thermoelectric properties of p-type Te-Sb₂Se₃: synergistic effect of doping and defect engineering. ACS Applied Materials & Interfaces, 2019, 11(31): 27788.
[35]	NORÉN L, TING V, WITHERS R L, et al. An electron and X-ray diffraction investigation of Ni₁₊_xTe₂ and Ni₁₊_xSe₂CdI₂/NiAs type solid solution phases. Journal of Solid State Chemistry, 2001, 161(2): 266.
[36]	ANDERSON J S. Nonstoichiometric compounds: a critique of current structural views. Proceedings of the Indian Academy of Sciences - Chemical Sciences, 1984, 93(6): 861.
[37]	CHEN J, ZHANG Y, YU Z, et al. Interface growth and void formation in Sn/Cu and Sn_0.7Cu/Cu systems. Applied Sciences, 2018, 8(12): 2703.
[38]	LIN Y, WU X, LI Y, et al. Revealing multi-stage growth mechanism of Kirkendall voids at electrode interfaces of Bi₂Te₃-based thermoelectric devices with in-situ TEM technique. Nano Energy, 2022, 102: 107736.
[39]	LIU R, XING Y, LIAO J, et al. Thermal-inert and ohmic-contact interface for high performance half-Heusler based thermoelectric generator. Nature Communications, 2022, 13(1): 7738.
[40]	BALL R G J, DICKINSON S, CORDFUNKE E H P, et al. Thermochemical data acquisition. Part II. Luxembourg: Commission of the European Communities, 1992: 106.
[41]	BARIN I. Thermochemical data of pure substances. 3rd ed. Weinheim: VCH Verlagsgesellschaft mbH, 1995: 1198.
[42]	叶贡欣. 扩散控制固相反应动力学关系的研究. 合肥水泥研究设计院院刊, 1992(1): 10.
[43]	陈立东, 刘睿恒, 史迅. 热电材料与器件. 北京: 科学出版社, 2018: 1.