Realizing Enhanced Thermoelectric Performance and Hardness in Icosahedral Cu5 FeS4-x Sex with High-Density Twin Boundaries

Huan Wang; Sikang Zheng; Hong Wu; Xin Xiong; Qihong Xiong; Hengyang Wang; Yang Wang; Bin Zhang; Xu Lu; Guang Han; Guoyu Wang; Xiaoyuan Zhou

doi:10.1002/smll.202104592

Realizing Enhanced Thermoelectric Performance and Hardness in Icosahedral Cu₅ FeS_4-_x Se_x with High-Density Twin Boundaries

Small. 2022 Jan;18(2):e2104592. doi: 10.1002/smll.202104592. Epub 2021 Nov 5.

Authors

Huan Wang¹, Sikang Zheng¹, Hong Wu¹, Xin Xiong¹, Qihong Xiong¹, Hengyang Wang², Yang Wang¹, Bin Zhang³, Xu Lu¹, Guang Han², Guoyu Wang^{4

5}, Xiaoyuan Zhou^{1

3}

Affiliations

¹ College of Physics, Chongqing University, Chongqing, 401331, P. R. China.
² College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, P. R. China.
³ Analytical and Testing Center, Chongqing University, Chongqing, 401331, P. R. China.
⁴ Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, P. R. China.
⁵ University of Chinese Academy of Sciences, Beijing, 100044, P. R. China.

PMID: 34741422
DOI: 10.1002/smll.202104592

Abstract

Bornite (Cu₅ FeS₄ ) is an Earth-abundant, nontoxic thermoelectric material. Herein, twin engineering and Se alloying are combined in order to further improve its thermoelectric performance. Cu₅ FeS_4-_x Se_x (0 ≤ x ≤ 0.4) icosahedral nanoparticles, containing high-density twin boundaries, have been synthesized by a colloidal method. Spark plasma sintering retains twin boundaries in the pellets sintered from Cu₅ FeS_4-_x Se_x colloidal powders. Thermoelectric property measurement demonstrates that alloying Se increases the carrier concentration, leading to much-improved power factor in Se-substituted Cu₅ FeS₄ , for example, 0.84 mW m^-1 K^-2 at 726 K for Cu₅ FeS_3.6 Se_0.4 ; low lattice thermal conductivity is also achieved, due to intrinsic structural complexity, distorted crystal structure, and existing twin boundaries and point defects. As a result, a maximum zT of 0.75 is attained for Cu₅ FeS_3.6 Se_0.4 at 726 K, which is about 23% higher than that of Cu₅ FeS₄ and compares favorably to that of reported Cu₅ FeS₄ -based materials. In addition, the Cu₅ FeS_4-_x Se_x samples containing twin boundaries also obtain improved hardness compared to the ones fabricated by melting-annealing or ball milling. This work demonstrates an effective twin engineering-composition tuning strategy toward enhanced thermoelectric and mechanical properties of Cu₅ FeS₄ -based materials.

Keywords: Cu 5FeS 4; hardness; icosahedron; thermoelectric materials; twin boundary.

Publication types

Research Support, Non-U.S. Gov't