Preparation And Properties Of CoSb₃ Filled Thermoelectric Materials

The skutterudite material is one of the most promising thermoelectric materials in the middle temperature region.Its special crystal structure makes it have the potential to be a phonon-electronic crystal.Increasing the ZT value of skutterudite material has always been the focus of research workers.Impurity atoms filling,nanostructures,and the second equal means of compounding can all reduce the thermal conductivity of skutterudite,thereby improving the overall thermoelectric performance.The traditional preparation process of skutterudite is to prepare powder by melting-annealing and then sintering.This method has a long preparation cycle and high cost,and long-term annealing may produce other phase impurities or lead to excessive grain growth and thermal conductivity of the material.It has picked up again.Different from the traditional process of preparing skutterudite materials,this paper uses hydrothermal synthesis method,uses low-cost compound raw materials,and uses the special chemical environment in the autoclave to promote the redox reaction and peritectic reaction,greatly shortening Synthesizing time,and using the unique chemical environment of hydrothermal method to improve the microstructure of the powder,nano-scale particles can further reduce the thermal conductivity of the material,to achieve the purpose of optimizing thermoelectric performance.Determining the chemical reaction parameters in the hydrothermal reactor can further control the reaction process,calculate the reaction thermodynamics and determine the reaction principle,so as to control the product structure and reaction process,and achieve precise control of the reaction process.In addition,using the SPS sintering process,the morphology of the sintering neck was first simulated and calculated,and the relationship between the sintering time and the density and sintering size was obtained.The optimal sintering time was comprehensively considered,the sintering parameters were determined,and the skutterudite was prepared.Block and complete the relevant performance test.In this paper,Ba atoms are filled into the vacancies of skutterudite to enhance the carrier concentration,thereby increasing its conductivity and Seebeck coefficient.At the same time,the phonon scattering is further enhanced by the filling of atomdisturbance and lattice defects caused by impurity atoms.Therefore,the thermal conductivity of the lattice is weakened,and finally the thermal conductivity of the macroblock is reduced,and its ZT value is increased.In the experiment,Ba single-filled samples Ba_yCo₄Sb₁₂ with different filling ratios were prepared?y=0,0.7,8,0.9,1.0?.The conductivity of the filled samples was improved by an order of magnitude compared to the unfilled samples.When y=0.7,the highest conductivity is 9.9×10⁴ S/m.Due to the influence of the microstructure,the power factor reaches a maximum of 8.5?w·cm^-1k^-1,when y=0.9.At the same time,due to lattice defects caused by mass fluctuations and volume fluctuations,the lattice thermal conductivity of the material is greatly reduced.When y=0.7,the minimum thermal conductivity is 2.3 W/?m·K?,so Ba_0.7Co₄Sb?12? comprehensive heat The performance and electrical performance are the best match,and the ZT value is the largest,reaching 0.23 at 700 K.