Zheng Yunpeng, Zhang Qinghua, Shi Caijuan, Zhou Zhifang, Lu Yang, Han Jian, Chen Hetian, Ma Yunpeng, Zhang Yujun, Lin Changpeng, Xu Wei, Ma Weigang, Li Qian, Yang Yueyang, Wei Bin, Yang Bingbing, Zou Mingchu, Zhang Wenyu, Liu Chang, Dou Lvye, Yang Dongliang, Lan Jin-Le, Yi Di, Zhang Xing, Gu Lin, Nan Ce-Wen, Lin Yuan-Hua
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, PR China.
Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Fuzhou, PR China.
Nat Commun. 2024 Sep 3;15(1):7650. doi: 10.1038/s41467-024-52063-5.
Thermoelectrics converting heat and electricity directly attract broad attentions. To enhance the thermoelectric figure of merit, zT, one of the key points is to decouple the carrier-phonon transport. Here, we propose an entropy engineering strategy to realize the carrier-phonon decoupling in the typical SrTiO-based perovskite thermoelectrics. By high-entropy design, the lattice thermal conductivity could be reduced nearly to the amorphous limit, 1.25 W m K. Simultaneously, entropy engineering can tune the Ti displacement, improving the weighted mobility to 65 cm V s. Such carrier-phonon decoupling behaviors enable the greatly enhanced μ/κ of ~5.2 × 10 cm K J V. The measured maximum zT of 0.24 at 488 K and the estimated zT of ~0.8 at 1173 K in (SrBaCaPbLa)TiO film are among the best of n-type thermoelectric oxides. These results reveal that the entropy engineering may be a promising strategy to decouple the carrier-phonon transport and achieve higher zT in thermoelectrics.
直接将热和电进行转换的热电器件引起了广泛关注。为了提高热电优值zT，关键要点之一是解耦载流子-声子输运。在此，我们提出一种熵工程策略，以在典型的基于SrTiO的钙钛矿热电材料中实现载流子-声子解耦。通过高熵设计，晶格热导率可降低至接近非晶极限，即1.25 W m⁻¹ K⁻¹。同时，熵工程可以调节Ti的位移，将加权迁移率提高到65 cm² V⁻¹ s⁻¹。这种载流子-声子解耦行为使得μ/κ大幅提高至约5.2×10⁻³ cm² K⁻¹ J⁻¹ V²。在(SrBaCaPbLa)TiO薄膜中，在488 K时测得的最大zT为0.24，在1173 K时估计的zT约为0.8，这在n型热电氧化物中是最好的之一。这些结果表明，熵工程可能是一种在热电材料中解耦载流子-声子输运并实现更高zT的有前景的策略。
