Approaching high thermoelectric performance in p-type Cu3SbS4-based materials by rational electronic and nano/microstructural engineering
Jingwen Yang, Xiao‐Lei Shi, Qishuo Yang, Weixia Shen, Meng Li, Zhuangfei Zhang, Wei‐Di Liu, Chao Fang, Yuanqing Mao, Qianqian Wang, Liangchao Chen, Biao Wan, Yuewen Zhang, Xiaopeng Jia, Zhi‐Gang Chen
Abstract
Due to the eco-friendly and earth-abundant features, p-type Cu3SbS4-based sulfides have shown great potential as cost-effective thermoelectric materials for practical applications in power generation and refrigeration. However, low electrical conductivities of p-type Cu3SbS4-based sulfides result in insufficient thermoelectric properties. In this work, a high average ZT of 0.45 and a maximum ZT of 0.85 at 623 K were obtained in Cu3SbS4-based sulfides through rational electronic and nano/microstructural engineering, achieved by mechanical alloying combined with fast spark plasma sintering techniques. Guided by theoretical calculations, we first study the physical properties of Cu3SbS4-xSex to explore the best composition (Cu3SbS3Se) that balances high thermoelectric performance, high thermal stability, and high mechanical performance. Based on this composition, we employed 4 % p-type AgSnSe2 with a narrow bandgap of ∼0.15 eV to further boost the electrical conductivity of Cu3SbS3Se, generating a high power factor of 12.65 μW cm−1 K−2 at 623 K. In addition, comprehensive nano/microstructural characterizations indicate that a combination of dense grain boundaries, phase boundaries, and multi-dimensional lattice defects acts as rich sources to intensely scatter multi-frequency phonons, leading to a decreased thermal conductivity of 0.93 W m−1 K−1 at 623 K. This work provides a new route to boost the thermoelectric properties of sulfides for practical applications.