Study On Preparation Of CNTs/La_0.1Sr_0.9TiO₃ Nano-thermoelectrical Composite Materials By LCS

Thermoelectric materials has become a hot research topic in the new energy materials,which can convert heat to electricity directly without any active components,and vice versa.SrTi O3 thermoelectric material has great application prospect in all kinds of thermoelectric materials.And the introduction of the nanostructure is an effective means to improve the performance of thermoelectric materials.CNTs have been widely used in composite materials due to the special structure and excellent properties.This paper creat a CNTs/La_0.1Sr_0.9TiO₃nano-thermoelectrical composites system combined with the advantages of them.Nano La_0.1Sr_0.9TiO₃ ceramic powders was prepared by LCS,we studied the influence of n?M?:n?CA?,reaction temperature and the precursor solution pH on product's quality,and optimizing the preparation condition to get high quality La_0.1Sr_0.9TiO₃ nano ceramic powders.Results show that the nano powders' grain size is 23.62 nm,crystallinity is 87.3% under the preparation condition n?M?:n?CA?= 1:1.5,T = 650?,pH = 7.LCS reduce the reaction temperature of the powders significantly compared with the traditional solid reaction method,but the powders have a serious hard agglomerate phenomenon which need to be further solved.CNTs/La_0.1Sr_0.9TiO₃ nano-thermoelectrical composites were prepared use purchased CNTs and La_0.1Sr_0.9TiO₃ powders prepared by traditional solid reaction method and LCS.We preliminary explored the preparation technology of CNTs/La0.1Sr0.9Ti O3 nanothermoelectrical composites,and studied the influence of samples components,different preparation methods and different preparation process on the microstructure.We also testing the thermalelectrical parameters of samples,in order to obtain materials with relatively simple preparation process,economic main raw material prices,environmental friendly,and high thermoelectric performance at the same time,provide theoretical and technical reference for development of high performance thermoelectric materials.We characterized the lattice structure and micro morphology of the composite ceramic and found that CNTs has a great influence on ceramic matrix.CNTs can not only make the ceramic lattice structure to be distorted,but also inhibit the growth of the grain which leads to grain size decrease.In terms of composite ceramic sintering,the results show that the traditional sintering process is not suitable for the preparation of CNTs/La_0.1Sr_0.9TiO₃ nanothermoelectrical composites due to the high sintering temperature and long sintering time.SPS method can prepared CNTs/La_0.1Sr_0.9TiO₃ nano-thermoelectrical composites successfullywhen the sintering temperature is 1000? and 1100?.However,the sample whose sintering temperature is 1000? has a low crystallinity due to the temperature is low relatively.And the sample resistance is too high to measure thermoelectrical parameter.We measured the thermoelectrical parameter of the sample whose Sintering temperature is 1100?,found that CNTs can improve S obviously,when T = 965 K,?S?= 262.57 ?V/K.However,the hole structure restricted the PF increase of the sample.