摘要
层状无机材料的弱层间耦合和大面积表面为构建低导热性无机固体材料提供了基本框架.合成具有足够散射和非谐波性的稳定层状材料,从而降低热导率,仍是一项挑战.本文在层状无机FeOCl材料体系中,通过一步氧化还原反应成功获得了一种结构稳定的富含Fe^(2+)的层状材料,实现了表面和界面的同步改性,并实现了超低的热导率.具体而言,系统的X射线吸收精细结构(XAFS)分析和电子能量损失光谱(EELS)分析表明,碱金属原子的层间插层和表面缺陷的引入诱导了大量Fe^(2+)的存在,从而增强了其非谐波性和声子散射.此外,声子态密度(PDOS)分布也提供了确凿的证据,证明了散射概率的提高和声子模式整体的软化.所制得的层状无机材料Fe(III)_(1−n)Fe(II)_(n)O_(1−x)Cl[K^(+)]_(m)不仅结构稳定,而且在298 K时的热导率比原始FeOCl降低了近60%,低至0.29 W m^(−1) K^(−1),这在层状无机材料中是极低的.这项研究为低导热层状材料的设计提供了新的视角.
The weak interlayer coupling and large-area surface of layered inorganic materials establish a fundamental framework for constructing inorganic solid materials with low thermal conductivity.It is still challenging to synthesize stable layered materials with sufficient scattering and anharmonicity,which can reduce thermal conductivity.Herein,in the layered inorganic FeOCl material system,a structurally stable Fe2+-rich layered materials is successfully obtained by a onestep redox reaction,which achieves simultaneous surface and interface modification and brings about an ultralow thermal conductivity.Specifically,systematic X-ray absorption fine structure(XAFS)analysis and electron energy loss spectroscopy(EELS)analysis show that the existence of a large amount of Fe2+induced by interlayer intercalation of alkali metal atoms and the introduction of surface defects,which enhances the anharmonicity and phonon scattering.Furthermore,the Phonon density of states(PDOS)distribution also gives a solid evidence to demonstrate that the enhancement of scattering probability and the softened overall of phonon pattern.The obtained layered inorganic materials Fe(III)_(1−n)Fe(II)_(n)O_(1−x)Cl[K^(+)]_(m) exhibit not only structural stability,but also an almost 60%decrease relative to pristine FeOCl of thermal conductivity at 298 K to as low as 0.29 W m^(−1) K^(−1),which is extremely low among layered inorganic materials.This work provides a new perspective on the design of low thermal conductivity layered materials.
作者
汪琳
周天培
台晓琳
王铭浩
王文杰
王纯
林岳
郭宇桥
谢毅
吴长征
Lin Wang;Tianpei Zhou;Xiaolin Tai;Minghao Wang;Wenjie Wang;Chun Wang;Yue Lin;Yuqiao Guo;Yi Xie;Changzheng Wu(Key Laboratory of Precision and Intelligent Chemistry,University of Science and Technology of China,Hefei 230026,China;Hefei National Research Center for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,China;National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei 230029,China;Institute of Energy Hefei Comprehensive National Science Center,Hefei 230031,China)
基金
supported by the Chinese Academy of Sciences(CAS)Project for Young Scientists in Basic Research(YSBR-070)
the National Natural Science Foundation of China(21925110,22321001 and 12147105)
the USTC Research Funds of the Double FirstClass Initiative(YD2060002004)
the National Key Research and Development Program of China(2022YFA1203600)
the Anhui Provincial Key Research and Development Project(202004a050200760)
the Key R&D Program of Shandong Province(2021CXGC010302)
the Fellowship of China Postdoctoral Science Foundation(2022M710141)
the Open Foundation of the Key Lab(Center)of Engineering Research Center of Building Energy Efficiency Control and Evaluation,Ministry of Education(AHJZNX-2023-04).
