Dong Zirui, Wang Chenxin, Chen Jiajun, Li Zhili, Dai Shengnan, Yan Xin, Zhang Jiye, Yang Jiong, Zhai Qijie, Luo Jun
School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China.
Materials Genome Institute, Shanghai University, Shanghai, 200444, China.
Small Methods. 2024 Jan;8(1):e2300829. doi: 10.1002/smtd.202300829. Epub 2023 Sep 20.
N-type ZrNiSn-based alloys reach a record thermoelectric figure of merit zT ≈1.2 by increasing the carrier concentration to 4-5 × 10 cm . In this work, It is reported that a comparable zT can also be realized in trace Ru-doped ZrNiSn-based alloy at even lower temperature by decreasing the carrier concentration. Compared to the previously reported Co doping, the doping of Ru results in a more effective reduction in carrier concentration, and thus higher Seebeck coefficient, lower electronic thermal conductivity, and enhanced thermoelectric performance. The electronic specific heat coefficient of the ZrNi Ru Sn sample remains constant with increasing Ru content, indicating no obvious change in the density of states effective mass. Theoretical calculations show that the doping of Ru has negligible effect on the bottom of conduction band. The lattice thermal conductivity is further reduced by alloying Ti and Hf at the Zr site, and the bipolar diffusion is suppressed by doping of 0.5 at.% Sb. As a result, Ti Zr Hf Ni Ru Sn Sb reaches not only a zT value of 1.1 at 773 K but also a record average zT value of 0.8 in 300 to 873 K, demonstrating the effectiveness of trace Ru doping on boosting the thermoelectric performance of ZrNiSn-based alloys.
通过将载流子浓度提高到4 - 5×10²¹ cm⁻³，N型ZrNiSn基合金的热电优值zT达到了约1.2的创纪录值。在这项工作中，据报道，通过降低载流子浓度，在痕量Ru掺杂的ZrNiSn基合金中，甚至在更低温度下也能实现相当的zT值。与先前报道的Co掺杂相比，Ru掺杂导致载流子浓度更有效地降低，从而具有更高的塞贝克系数、更低的电子热导率和增强的热电性能。ZrNi₁₋ₓRuₓSn样品的电子比热系数随Ru含量的增加保持不变，表明有效质量态密度没有明显变化。理论计算表明，Ru掺杂对导带底部的影响可忽略不计。通过在Zr位点合金化Ti和Hf进一步降低了晶格热导率，并且通过0.5 at.%的Sb掺杂抑制了双极扩散。结果，Ti₀.₅Zr₀.₅HfNi₀.₉₉₅Ru₀.₀₀₅Sn₀.₉₉₅Sb不仅在773 K时达到了1.1的zT值，而且在300至873 K范围内达到了0.8的创纪录平均zT值，证明了痕量Ru掺杂对提高ZrNiSn基合金热电性能的有效性。
