Oxide-based ceramics could be promising thermoelectric materials because of their thermal and chemical stability at high temperature.However,their mediocre electrical conductivity or high thermal conductivity is still...Oxide-based ceramics could be promising thermoelectric materials because of their thermal and chemical stability at high temperature.However,their mediocre electrical conductivity or high thermal conductivity is still a challenge for the use in commercial devices.Here,we report significantly suppressed thermal conductivity in SrTiO_(3)-based thermoelectric ceramics via high-entropy strategy for the first time,and optimized electrical conductivity by defect engineering.In high-entropy(Ca_(0.2)Sr_(0.2)Ba_(0.2)Pb_(0.2)La_(0.2))TiO_(3)bulks,the minimum thermal conductivity can be 1.17 W/(m·K)at 923 K,which should be ascribed to the large lattice distortion and the huge mass fluctuation effect.The power factor can reach about 295μW/(m·K^(2))by inducing oxygen vacancies.Finally,the ZT value of 0.2 can be realized at 873 K in this bulk sample.This approach proposed a new concept of high entropy into thermoelectric oxides,which could be generalized for designing high-performance thermoelectric oxides with low thermal conductivity.展开更多
Flexible thermoelectric materials are presented with potential applications in electronic devices and energy conversion due to their convenient preparation,good flexibility,and various forms.However,as ductility is ra...Flexible thermoelectric materials are presented with potential applications in electronic devices and energy conversion due to their convenient preparation,good flexibility,and various forms.However,as ductility is rarely observed in inorganic semiconductors and ceramic insulators,reports on applications of inorganic oxide materials in flexible thermoelectric materials are sparse.Here,we report a new method for the synthesis of a flexible Na_(1.4)Co_(2)O_(4) thermoelectric material based on Na_(1.4)Co_(2)O_(4) bulk materials,which are prepared by a self-flux method and painted on print paper.Seebeck coefficient and power factor of the obtained thermoelectric material are 78-102 μVK^(-1) and 159e223 mWm^-(1)K^(-2),respectively,in a temperature range of 303-522 K,which are superior to those values of other conductive polymers and their compounds.More interestingly,the n-type Na_(1.4)Co_(2)O_(4) flexible material is obtained in the painting process at higher pressure with Seebeck coefficients of109 to183 μVK^(-1) in a temperature range of 303-522 K.The convenient preparation method of these novel flexible thermoelectric materials may be expanded to the synthesis of other flexible thermoelectric materials,which will be the focus of future work.展开更多
基金financially supported by Basic Science Center Project of the National Natural Science Foundation of China under Grant No.51788104National Key Research Program of China under Grant No.2016YFA0201003the National Natural Science Foundation of China under Grant No.51729201。
文摘Oxide-based ceramics could be promising thermoelectric materials because of their thermal and chemical stability at high temperature.However,their mediocre electrical conductivity or high thermal conductivity is still a challenge for the use in commercial devices.Here,we report significantly suppressed thermal conductivity in SrTiO_(3)-based thermoelectric ceramics via high-entropy strategy for the first time,and optimized electrical conductivity by defect engineering.In high-entropy(Ca_(0.2)Sr_(0.2)Ba_(0.2)Pb_(0.2)La_(0.2))TiO_(3)bulks,the minimum thermal conductivity can be 1.17 W/(m·K)at 923 K,which should be ascribed to the large lattice distortion and the huge mass fluctuation effect.The power factor can reach about 295μW/(m·K^(2))by inducing oxygen vacancies.Finally,the ZT value of 0.2 can be realized at 873 K in this bulk sample.This approach proposed a new concept of high entropy into thermoelectric oxides,which could be generalized for designing high-performance thermoelectric oxides with low thermal conductivity.
基金This project was supported by the National Natural Science Foundation of China under the Nos.51702168 and 51927801the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure under the No.SKL201705SICthe Inner Mongolia Engineering Research Center of Multifunctional Copper Materials.
文摘Flexible thermoelectric materials are presented with potential applications in electronic devices and energy conversion due to their convenient preparation,good flexibility,and various forms.However,as ductility is rarely observed in inorganic semiconductors and ceramic insulators,reports on applications of inorganic oxide materials in flexible thermoelectric materials are sparse.Here,we report a new method for the synthesis of a flexible Na_(1.4)Co_(2)O_(4) thermoelectric material based on Na_(1.4)Co_(2)O_(4) bulk materials,which are prepared by a self-flux method and painted on print paper.Seebeck coefficient and power factor of the obtained thermoelectric material are 78-102 μVK^(-1) and 159e223 mWm^-(1)K^(-2),respectively,in a temperature range of 303-522 K,which are superior to those values of other conductive polymers and their compounds.More interestingly,the n-type Na_(1.4)Co_(2)O_(4) flexible material is obtained in the painting process at higher pressure with Seebeck coefficients of109 to183 μVK^(-1) in a temperature range of 303-522 K.The convenient preparation method of these novel flexible thermoelectric materials may be expanded to the synthesis of other flexible thermoelectric materials,which will be the focus of future work.
