Materials Today Physics
·
2020
·
IF 10.443
Juan Li,Shuai Zhang,Fei Jia,Shuqi Zheng,Xiaolei Shi,Daqiang Jiang,Siyu Wang,Guiwu Lu,Liming Wu,Zhi-Gang Chen
Approaching practical thermoelectric devices require high-performance and machinable thermoelectric materials . However, the currently available materials are usually brittle. In this work, Nd-doped Mg 3 Sb 2 -based compounds exhibit not only excellent thermoelectric performance but also superior machinability . Mg 3.2 Nd 0.03 Sb 1.5 Bi 0.5 exhibits a high power factor of 20.6 μW cm −1 K −2 at 725 K and a peak zT of 1.8, which mainly originates from the increased n of ~8 × 10 19 cm −3 by Nd/Mg substitutional defects. Defect calculations predict that other rare earth elements (Sm, Gd, Tb, Dy and Ho) have the same effect as Nd on Mg 3 Sb 2 and the predicted highest achievable electron concentrations at 700 K are ~10 20 cm −3 . The measured hardness, Young's modulus and fracture toughness of Mg 3.2 Nd 0.03 Sb 1.5 Bi 0.5 are 1.1 GPa, 49.8 GPa and 1.4 MPa m 1/2 , respectively. In addition, the sample can be easily machined into the dog-bone shape with external thread at both ends, indicating the excellent machinability of Mg 3 Sb 2 -based materials. This work suggests a bright future of Mg 3 Sb 2 -based thermoelectric materials for practical applications and device fabrication .
研究领域:
材料科学
·
热电材料研究
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Jisheng Liang,Hengquan Yang,Chengyan Liu,Lei Miao,Junliang Chen,Sijing Zhu,Zhengchuan Xie,Wenjing Xu,Xiaoyang Wang,Jun Wang,Biaolin Peng,Kunihito Koumoto
Mg3Sb2-based compounds by virtue of nontoxicity and low-cost have become a promising class of candidates for midtemperature thermoelectric power generation. Here, we successfully fabricated n-type Mg3Sb2-based materials using an inexpensive and efficient approach of one-step ball milling and spark plasma sintering, and demonstrate that a complementary and favorable effect of multiple elements coalloying/-doping leads to an excellent thermoelectric performance. The intrinsic p-type conducting behavior for Mg3Sb2 could be changed to n-type through Bi and Se coalloying on Sb sublattices with excess Mg, resulting from the suppression of Mg vacancies and the formation of Mg interstitial. Furthermore, Mn doping on Mg sublattices could soften the chemical bonds, leading to the increase of carrier mobility and concentration simultaneously. Additionally, multielement coalloying/-doping could significantly increase the lattice disorder, which undoubtedly strengthens the phonon scattering and readily results in a suppressed lattice thermal conductivity. As a result, a highest ZT value of 1.6 at 723 K and an average ZT value up to 1.1 were obtained in the temperature range of 323–723 K in the Mg3.18Mn0.02Sb1.5Bi0.49Se0.01 sample, which is one of the highest values among the Te free Mg3Sb2. This work could give guidance for improving the thermoelectric performance of Zintl phase materials or even others using the multielement codoping/-alloying strategy.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
PubMed
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2022
·Vol. 24
·期 45
·27812-27818
·
IF 3.945
Juan Li,Fei Jia,Kai Han,Bing Sun,Lianzhen Cao,Yingde Li,Shuai Zhang
Experimental results show an intriguing phenomenon that although Bi and Sb have the same number of valence electrons, Bi/Sb substitution increases the electron concentration of n-type Mg3Sb2-based materials. Using a combination of theoretical calculations and experimental synthesis, this work reveals the physical mechanism of the effect of Bi doping on carrier concentration. The increase in electron concentration mainly originates from the enhanced degree of ionization of donor impurity because of the decrease of conductivity effective mass and increase of dielectric constant caused by the narrowing of bandgap with Bi doping. Based on the collaborative optimization of the electrical and thermal transports, n-type Mg3.175Mn0.025Sb1.48Bi0.48Te0.04 exhibits the best thermoelectric performance with a peak zT of 1.85 at 725 K and an average zT of 1.21. This work demonstrates an effective strategy of bandgap engineering for the optimization of carrier concentration and provides insightful guidance for designing other thermoelectric materials.
研究领域:
材料科学
·
凝聚态物理
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yu Jiang,Marhoun Ferhat,Wenhao Fan,Shaoping Chen,Yachao Wang,Jie Chen,Rasha Abdullah Ahmed Al-Yusufi,Chaochao Dun
Additional cation doping is one of the potential strategies to enhance the thermoelectric (TE) performance of Mg 3 Sb 2 -based materials with precise regulation of interaction between cations and the host. In this work, using Mg 3 Sb 1.5 Bi 0.5 as an example, we confirmed that co-doping rare-earth elements with Y and La is capable to simultaneously improve its power factor and suppress the thermal conductivity : Y is an effective n -type dopant to regulate the optimal carrier concentration, while La doping can modulate the band structure and increase the effective mass that related to the improved Seebeck coefficient . A promising power factor of 18.3 μW cm -1 K -2 is obtained after co-doping. Meanwhile, the lattice thermal conductivity is dramatically reduced to 0.39 W m -1 K -1 at 750 K thanks to the extra defect scattering introduced by Y and La. As a result, a peak figure of merit ( zT ) of 1.76 and a competitive average zT of 1.1 among 300–750 K are achieved in Mg 3.2 Y 0.04 La 0.01 Sb 1.5 Bi 0.5 . The synergistic effect stemming from dual-cations doping provides profound insights for controllable host-dopant design and modulation toward high-efficient n-type TE materials .
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
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