Mao Tao, Qiu Pengfei, Hu Ping, Du Xiaolong, Zhao Kunpeng, Wei Tian-Ran, Xiao Jie, Shi Xun, Chen Lidong
State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China.
Adv Sci (Weinh). 2019 Oct 19;7(1):1901598. doi: 10.1002/advs.201901598. eCollection 2020 Jan.
Liquid-like materials are one family of promising thermoelectric materials discovered in the past years due to their advantanges of ultrahigh thermoelectric figure of merit (), low cost, and environmental friendliness. However, their practial applications are greatly limited by the low service stability from the Cu/Ag metal deposition under large current and/or temperature gradient. Both high for high efficiency and large critical voltage for good stability are required for liquid-like materials, but they are usually strongly correlated and hard to be tuned individually. Herein, based on the thermodynamic analysis, it is shown that such a correlation can be decoupled through doping immobile ions into the liquid-like sublattice. Taking Cu S as an example, doping immobile Fe ions in CuS scarcely degrades the initial large critical voltage, but significantly enhances the to 1.5 at 1000 K by tuning the carrier concentration to the optimal range. Combining the low-cost and environmentally friendly features, these Fe-doped Cu S-based compounds show great potential in civil applications. This study sheds light on the realization of both good stability and high performance for many other liquid-like thermoelectric materials that have not been considered for real applications before.
类液体材料是过去几年发现的一类很有前景的热电材料，因其具有超高的热电优值、低成本和环境友好等优点。然而，在大电流和/或温度梯度下，铜/银金属沉积导致的低服役稳定性极大地限制了它们的实际应用。类液体材料既需要高热电优值以实现高效，又需要大的临界电压以保证良好的稳定性，但它们通常紧密相关，难以单独调节。在此，基于热力学分析表明，通过向类液体亚晶格中掺杂不动离子可以解除这种相关性。以Cu₂S为例，在CuS中掺杂不动的Fe离子几乎不会降低初始的大临界电压，但通过将载流子浓度调节到最佳范围，在1000 K时可将热电优值显著提高到1.5。结合低成本和环境友好的特点，这些掺Fe的Cu₂S基化合物在民用应用中显示出巨大潜力。这项研究为许多以前未考虑实际应用的其他类液体热电材料实现良好稳定性和高性能提供了思路。
