Coherent Ag-rich nanoprecipitates/β-Ag2Se flexible film with unprecedented thermoelectric performance by liquid-like sintering

Jie Gao; Jiahui Li; Lei Miao; Lida Jia; Pengfei Qiu; Tingwei Yin; Sijing Zhu; Xinyu Yang; Jia-Chen Guo; Jun-Liang Chen; Xiaoyang Wang; Eiji Nishibori; Tomohiro Sato; Xun Shi

doi:10.1038/s41467-025-61079-4

Coherent Ag-rich nanoprecipitates/β-Ag₂Se flexible film with unprecedented thermoelectric performance by liquid-like sintering

Nat Commun. 2025 Jul 1;16(1):6010. doi: 10.1038/s41467-025-61079-4.

Authors

Jie Gao¹, Jiahui Li¹, Lei Miao², Lida Jia¹, Pengfei Qiu³, Tingwei Yin³, Sijing Zhu⁴, Xinyu Yang⁴, Jia-Chen Guo¹, Jun-Liang Chen¹, Xiaoyang Wang⁴, Eiji Nishibori⁵, Tomohiro Sato⁶, Xun Shi⁷

Affiliations

¹ Guangxi Key Laboratory of Information Materials, Engineering Research Center of Electronic Information Materials and Devices, Ministry of Education, Guilin University of Electronic Technology, Guilin, P. R. China.
² Guangxi Novel Battery Materials Research Center of Engineering Technology, School of Physical Science and Technology, Guangxi University, Nanning, China. miaolei@gxu.edu.cn.
³ State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China.
⁴ Guangxi Novel Battery Materials Research Center of Engineering Technology, School of Physical Science and Technology, Guangxi University, Nanning, China.
⁵ Department of Physics, Faculty of Pure and Applied Science, Tsukuba Research Center for Energy Materials Science (TREMS), Hydrogen Boride Research Center (HBRC), Tsukuba Institute for Advanced Research (TIAR), University of Tsukuba, Tsukuba, Ibaraki, Japan.
⁶ Sinter Land INC., Nagaoka, Niigata, Japan.
⁷ State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China. xshi@mail.sic.ac.cn.

Abstract

β-Ag₂Se holds a great promise for wearable thermoelectric generators due to its good mechanical properties and biocompatibility. However, optimizing its power factor through alterations in the Ag/Se stoichiometric ratio or incorporating secondary phases has reached the limitation. This work adopts a liquid-like sintering strategy, namely employing the migration and precipitation of silver ions from metallic silver to the silver selenide during the spark plasma sintering process to construct significantly sized and coherent Ag-rich nanoprecipitates within flexible Ag/β-Ag₂Se composite films, thereby achieving an unprecedented power factor exceeding 4000 μWm^-1K^-2 at 303 K. The Ag-rich nanoprecipitates play a crucial role in elevating the carrier concentration, enhancing the density-of-states effective mass, and mitigating carrier scattering caused by phase interfaces and acoustic phonons. The generator containing 5 pieces of optimal films shows an normalized output power density of 10.89 μWcm^-1K^-2 under a temperature difference of 26.0 K. This study strongly suggests that the creation of Ag-rich nanoprecipitates is an effective avenue for improving the electrical performance of β-Ag₂Se-based thermoelectric materials.

Grants and funding

U21A2054/National Natural Science Foundation of China (National Science Foundation of China)