Annealing engineering induced high thermoelectric performance in Yb-filled CoSb_(3) skutterudites  

作　　者：Haoran Feng Qian Deng Yan Zhong Xuri Rao Yadong Wang Jianglong Zhu Fujie Zhang Ran Ang 

机构地区：[1]Key Laboratory of Radiation Physics and Technology,Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China [2]Institute of New Energy and Low-Carbon Technology,Sichuan University,Chengdu 610065,China

出　　处：《Journal of Materials Science & Technology》2023年第19期168-174,共7页材料科学技术（英文版）

基　　金：supported by the National Key Research and Development Program of China (Grant Nos.2018YFA0702100 and 2022YFB3803900);the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences (CAS)’Large-Scale Scientific Facility (Grant No.U1932106);the Sichuan University Innovation Research Pro-gram of China (Grant No.2020SCUNL112).

摘　　要：The great pressure of energy shortage has made CoSb_(3) materials with excellent mechanical stability in the mid-temperature region favored for the integration of thermoelectric devices.However,their ex-cessive lattice thermal conductivity and poor Seebeck coefficient lead to low energy conversion effi-ciency.Filling Yb into the lattice void to optimize the band structure and regulate the chemical po-tential is an indispensable means for improving the thermoelectric properties of CoSb_(3)-based materials,while the phase structure and thermoelectric properties vary with the preparation process.This motivates the current work to focus on the influence of annealing temperature on the microstructure and thermoelectric properties of Yb-filled CoSb_(3).Experimental analysis and theoretical model eluci-dated that an increase in annealing temperature can optimize the Yb filling fraction,which simulta-neously manipulates the band structure as well as chemical potential,resulting in an excellent electrical property.Furthermore,the phase and microstructure characterization clarify that the annealing temperature can effectively affect the grain size.The complex grain boundary induced by grain refinement,more filled Yb atoms and precipitates strongly scatter wide-frequency phonons,significantly suppressing the lattice thermal conductivity.As a result,a superior dimensionless figure of merit(ZT)value of~1.33 at 823 K and an average ZTave of~0.9(323-823 K)were achieved in the Ybo.4Co4Sb12 sample annealed at 923 K,and the calculated conversion efficiency could reach~13%.This work pro-vides a unique paradigm to improve thermoelectrics in the filled CoSb_(3)-based skutterudites by annealing engineering.

关 键 词：CoSb_(3)skutterudite Annealing engineering Grain refinement Phonon scattering Thermoelectric optimization 

分 类 号：TB383.2[一般工业技术—材料科学与工程]