Boosting thermoelectric efficiency of Ag_(2)Se through cold sintering process with Ag nano-precipitate formation  

作　　者：Dejwikom Theprattanakorn Thanayut Kaewmaraya Supree Pinitsoontorn 

机构地区：[1]Department of Physics,Faculty of Science,Khon Kaen University,Khon Kaen 40002,Thailand [2]Institute of Nanomaterials Research and Innovation for Energy(IN-RIE),Khon Kaen University,Khon Kaen 40002,Thailand

出　　处：《International Journal of Minerals,Metallurgy and Materials》2024年第12期2760-2769,共10页矿物冶金与材料学报（英文版）

基　　金：supported by the National Research Council of Thailand(NRCT)(Nos.N42A650237 and N41A661163);the National Science,Research and Innovation Fund(NSRF)via the Fundamental Fund of Khon Kaen University;the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation(No.B37G660011).

摘　　要：Silver selenide(Ag_(2)Se)stands out as a promising thermoelectric(TE)material,particularly for applications near room temper-atures.This research presents a novel approach for the fabrication of bulk Ag_(2)Se samples at a relatively low temperature(170℃)using the cold sintering process(CSP)with AgNO_(3)solution as a transient liquid agent.The effect of AgNO_(3)addition during CSP on the micro-structure and TE properties was investigated.The results from phase,composition and microstructure analyses showed that the introduc-tion of AgNO_(3)solution induced the formation of Ag nano-precipitates within the Ag_(2)Se matrix.Although the nano-precipitates do not af-fect the phase and crystal structure of orthorhombicβ-Ag_(2)Se,they suppressed crystal growth,leading to reduced crystallite sizes.The samples containing Ag nano-precipitates also exhibited high porosity and low bulk density.Consequently,these effects contributed to sig-nificantly enhanced electrical conductivity and a slight decrease in the Seebeck coefficient when small Ag concentrations were incorpor-ated.This resulted in an improved average power factor from~1540μW·m^(−1)·K^(−2)for pure Ag_(2)Se to~1670μW·m^(−1)·K^(−2)for Ag_(2)Se with additional Ag precipitates.However,excessive Ag addition had a detrimental effect on the power factor.Furthermore,thermal conductiv-ity was effectively suppressed in Ag_(2)Se fabricated using AgNO_(3)-assisted CSP,attributed to enhanced phonon scattering at crystal inter-faces,pores,and Ag nano-precipitates.The highest figure-of-merit(zT)of 0.92 at 300 K was achieved for the Ag_(2)Se with 0.5wt%Ag dur-ing CSP fabrication,equivalent to>20%improvement compared to the controlled Ag_(2)Se without extra Ag solution.Thus,the process outlined in this study presents an effective strategy to tailor the microstructure of bulk Ag_(2)Se and enhance its TE performance at room temperature.

关 键 词：THERMOELECTRIC silver selenide CHALCOGENIDE cold sintering process nano-precipitate 

分 类 号：TB34[一般工业技术—材料科学与工程]