Faculty of Materials Science and Engineering, Kunming University of Science and Technology , Kunming 650093, China.
Shenzhen Key Laboratory of Thermoelectric Materials, Department of Physics, South University of Science and Technology of China , Shenzhen 518055, China.
ACS Appl Mater Interfaces. 2017 Feb 8;9(5):4828-4834. doi: 10.1021/acsami.6b14803. Epub 2017 Jan 25.
Bismuth sulfide (BiS) has been of high interest for thermoelectric applications due to the high abundance of sulfur on Earth. However, the low electrical conductivity of pristine BiS results in a low figure of merit (ZT). In this work, BiS@Bi core-shell nanowires with different Bi shell thicknesses were prepared by a hydrothermal method. The core-shell nanowires were densified to Bi/BiS nanocomposite by spark plasma sintering (SPS), and the structure of the nanowire was maintained as the nanocomposite due to rapid SPS processing and low sintering temperature. The thermoelectric properties of bulk samples were investigated. The electrical conductivity of a bulk sample after sintering at 673 K for 5 min using BiS@Bi nanowire powders prepared by treating BiS nanowires in a hydrazine solution for 3 h is 3 orders of magnitude greater than that of a pristine BiS sample. The nanocomposite possessed the highest ZT value of 0.36 at 623 K. This represents a new strategy for densifying core-shell powders to enhance their thermoelectric properties.
硫化铋（BiS）由于地球硫资源丰富，因此在热电应用中受到了广泛关注。然而，纯 BiS 的电导率较低，导致其品质因数（ZT）较低。在这项工作中，通过水热法制备了不同 Bi 壳厚度的 BiS@Bi 核壳纳米线。通过火花等离子烧结（SPS）将核壳纳米线致密化成为 Bi/BiS 纳米复合材料，由于 SPS 处理速度快且烧结温度低，纳米线结构在纳米复合材料中得以保留。研究了块体样品的热电性能。用 BiS 纳米线在联氨溶液中处理 3 小时制备的 BiS@Bi 纳米线粉末，在 673 K 下烧结 5 分钟后，块状样品的电导率比纯 BiS 样品高 3 个数量级。该纳米复合材料在 623 K 时具有最高的 ZT 值为 0.36。这代表了一种致密化核壳粉末以提高其热电性能的新策略。
