J. Mater. Sci. Technol. ›› 2026, Vol. 248: 189-198.DOI: 10.1016/j.jmst.2025.05.046

• Research article • Previous Articles     Next Articles

Cu ions migration modulation advances thermoelectric performance in copper selenides

Yi-Xin Zhanga,b, Xi Yana,b, Xing Yanga,b, Lan Yua, Yue-Xing Chenc, Ding-Yi Yud, Zulai Lia,b, Zhen-Hua Gea,b,*, Jiushuai Dengd,*, Jing Fenga,b,*   

  1. aFaculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China;
    bNational-Local Joint Engineering Research Center for Technology of Advanced Metallic Solidification Forming and Equipment, Kunming 650093, China;
    cShenzhen University, Coll Phys & Optoelect Engn, Shenzhen Key Lab Adv Thin Films & Applicat, Key Lab Optoelect Devices & Syst, Minist Educ & Gua, Shenzhen 518060, China;
    dKey Laboratory of Separation and Processing of Symbiotic-Associated Mineral Resources, Engineering Technology Research Center for Comprehensive Utilization of Rare Earth-Rare Metal-Rare Scattered in Non-ferrous Metal Industry, School of Chemical & Environmental Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China
  • Received:2025-03-06 Revised:2025-04-29 Accepted:2025-05-05 Published:2026-03-20 Online:2025-06-30
  • Contact: *E-mail addresses: zge@kust.edu.cn (Z.-H. Ge), jsdeng@cumtb.edu.cn (J. Deng), jingfeng@kust.edu.cn (J. Feng)

Abstract: Ion-blocking barriers play a key role in improving the electrical stability of superionic conductors. However, simultaneous enhancement of the thermoelectric performance and stability of superionic conductors requires a compromise among carrier, phonon, and ion propagation. In this study, a strategy of Cu ions migration modulation by compositing macroscopic and insulating phlogopite into Cu-based superionic conductors is proposed, which is effective in improving the thermoelectric properties and stability of copper selenide. The adverse effect of Cu ions migration on carrier transport was weakened at high temperatures for the composites by the phlogopite sheets. Multiscale lattice defects, including point defects, dislocations, nanopores, and nanoprecipitates, in copper selenide will help strengthen all-scale phonon scattering, reducing the lattice thermal conductivity of composites. A peak ZT value of 2.5 is yielded at 973 K in the composite due to the maintained electrical transport properties and significantly reduced thermal conductivity. The stability of the bulk composite and thermoelectric module was improved owing to the suppressed Cu-ion migration and the constructed voltage division circuit by the insulating phlogopite sheets. These findings help gain a deep understanding of the role played by macroscopic insulating phlogopite in manipulating Cu ions migration for enhancing the thermoelectric performance and stability of other Cu-based superionic conductors.

Key words: Copper slenide, Phlogopite, Cu ions migration, Thermoelectric performance, Stability