Enhanced Thermoelectric Performance of Yb-Filled Skutterudite with Bottom-Up Formed CoSi2 Nanoparticles

• Published in: ACS applied materials & interfaces Vol. 14; no. 51; pp. 56948 - 56956
• Main Authors: Shi, Wenjing, Du, Qing, Niu, Changlei, Qin, Dandan, Sun, Yuxin, Zhu, Jianbo, Li, Fushan, Xie, Liangjun, Liu, Zihang, Zhang, Qian, Cai, Wei, Guo, Fengkai, Li, Xin, Sui, Jiehe
• Format: Journal Article
• Language: English
• Published: American Chemical Society 28.12.2022
• Subjects: Functional Inorganic Materials and Devices; phonon scattering; thermoelectric; skutterudite; nanostructures; energy filtering
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.2c15413

It is known that Yb-filled skutterudite with excellent thermoelectric performance is promising for a power generation device in the intermediate temperature region. Here we created a new approach to obtain nanostructured materials by adding Si to Co-overstoichiometric Yb-filled skutterudite through high-energy ball milling, which embedded bottom-up formed CoSi2 nanoparticles into grain-refining Yb0.25Co4Sb12, synergistically resulting in the enhanced thermoelectric properties and room-temperature hardness. On one hand, the abundant grain boundaries and phase interfaces effectively blocked the propagation of medium-low frequency phonons, resulting in a lower lattice thermal conductivity. On the other hand, phase interfaces barrier nicely screened a portion of low-energy electrons, leading to an improved power factor. As a result, an enhanced peak ZT value of ∼1.43 at 823 K and a promising average ZT of ∼1.00 between 300 and 823 K were achieved in the Yb0.25Co4Sb12/0.05CoSi2 sample. Meanwhile, such nanostructures also enhanced the hardness through the collective contributions of second phase and fine grain strengthening, which made skutterudite more competitive in practical application.