材料科学
晶界
热电效应
烧结
纳米结构
热电材料
粒度
晶粒生长
纳米技术
热导率
冶金
复合材料
微观结构
热力学
物理
作者
Pengfei Xu,Wei Zhao,Xixi Liu,Baohai Jia,Jiaqing He,Liangwei Fu,Biao Xu
标识
DOI:10.1002/adma.202202949
摘要
Nanostructure engineering is a key strategy for tailoring properties in the fields of batteries, solar cells, thermoelectrics, and so on. Limited by grain coarsening, however, the nanostructure effect gradually degrades during the materials' manufacturing and in-service period. Herein, a strategy of cleavage-fracture for grain shrinking is developed in a Pb0.98 Sb0.02 Te sample during sintering, and the grain size remains stable after repeated tests. Moreover, the initial grain boundary is filled by fractured slender grains and enriched by dislocations, evolving into a hierarchical grain-boundary structure. The lattice thermal conductivity (klat ) is greatly reduced to approach the amorphous limit. As a result, a record-high ZT value of ≈1.9 is obtained at 815 K in the n-type Pb0.98 Sb0.02 Te sample and a decent efficiency of 6.7% in thermoelectric device. This strategy for grain shrinking will shed light on the application of nanostructure engineering under high temperature and extreme conditions in other material systems.
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