Gu Yan, Song Kaikai, Hu Xiaohui, Chen Changchun, Pan Lin, Lu Chunhua, Shen Xiaodong, Koumoto Kunihito, Wang Yifeng
College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China.
Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 210009, China.
ACS Appl Mater Interfaces. 2020 Sep 16;12(37):41687-41695. doi: 10.1021/acsami.0c09592. Epub 2020 Sep 1.
Layered 1T-type TiS powders were pretreated by an ethanol-based shear pulverization process, which showed outstanding effectiveness in reducing the average grain size and narrowing the size distribution while maintaining high crystallinity and plate-shaped morphology. The resulting bulk ceramics densified by spark plasma sintering possessed a highly (00)-oriented texture and pronounced anisotropy. They showed a noticeably increased σ and an unaffected in the in-plane direction due to the increased carrier mobility μ and the constant carrier concentration , which resulted in a significant enhancement of the in-plane power factor, optimally to an unprecedented high level of 1.6-1.8 mW m K in a range of 323-673 K. Meanwhile, the lattice thermal conductivity was reduced by approximately 20% due to the intensified grain boundary phonon scattering that overwhelmed the effect due to texturing. These effects not only demonstrated the powder shear pulverization pretreatment as a facial and reliable route toward a high-textured TiS but also enabled a remarkable increase of record for TiS-based thermoelectrics (TEs) to approximately 0.7 at 673 K, indicating clearly the significant effect of texture engineering on TE performance.
层状1T型TiS粉末通过乙醇基剪切粉碎工艺进行预处理，该工艺在降低平均晶粒尺寸和缩小尺寸分布方面表现出卓越的效果，同时保持了高结晶度和板状形态。通过放电等离子烧结致密化得到的块状陶瓷具有高度的（00）取向织构和明显的各向异性。由于载流子迁移率μ增加和载流子浓度不变，它们在面内方向上的σ显著增加而 不受影响，这导致面内功率因数显著提高，在323 - 673 K范围内最佳可达前所未有的高水平1.6 - 1.8 mW m K。同时，由于强烈的晶界声子散射超过了织构效应，晶格热导率降低了约20%。这些效应不仅证明了粉末剪切粉碎预处理是获得高织构TiS的一种简便可靠的途径，而且使基于TiS的热电材料（TEs）在673 K时的 记录显著提高到约0.7，清楚地表明了织构工程对TE性能的显著影响。
