| With the development of the aerospace industry,miniaturized radioisotope thermoelectric generators?RTG?are becoming ever more important,but at present,isotope thermoelectric generators are generally bulky.Therefore,this study used electrodeposition method to prepare bismuth tellurium-based thermoelectric thin film materials,and applied this material to prepare a new fan-shaped structure radioisotope thermoelectric generator.The preparation and performance optimization were studied from two aspects of materials and battery devices.The main research contents are summarized as follows:1)The n-type Bi-Te based thermoelectric film materials were prepared by electrodeposition.The effects of deposition potential and annealing temperature on the microscopic morphology,crystallization properties and film composition of the n-type films were studied.The thermoelectric properties of the materials were also analyzed.It is found that the optimal pulse deposition potential of the n-type material is 0 V,the morphology of the film is needle-like,and the film composition is Bi1.92Te3.08.The Bi-Te film has the best thermoelectric performance under this preparation conditions.Seebeck coefficient is-92.166?V/K,the conductivity value is 956.3 S/cm,and the power factor reaches the maximum value of 812.34?W/m·K2.The optimum annealing temperature of the n-type material is300°C,and the maximum power factor is 1103.59?W/m·K2,which is 35.85%higher than that of the unannealed material.2)The p-type Bi-Sb-Te based thermoelectric film materials were prepared by electrodeposition.The effects of electrolyte composition,deposition potential and annealing temperature on the microscopic morphology,crystallization properties and film composition of p-type films were studied.The thermoelectric properties of the materials were likewise analyzed.It is found that the optimal electrolyte Sb/Bi ratio of p-type material is 6,and the optimum deposition potential is-0.12 V.At this time,the film morphology is circular and the film composition is Bi0.68Sb1.24Te3.08,Seebeck coefficient of the Bi-Sb-Te film is 114.03?V/K,the conductivity value is 105.49 S/cm,and the thermoelectric power factor reaches the maximum value of 137.18?W/m·K2.The optimum annealing temperature for p-type materials is 250°C,and the material's power factor is 153.37?W/m·K2,which is 11.8%higher than that of the unannealed materials.3)The new fan-shaped structure was proposed to replace the traditional?-type structure,and the electrodeposited bismuth tellurium-based film material was used to prepare a novel fan-shaped isotope thermoelectric generator.The fan-shaped structure has the advantage of accommodating a large number of thermoelectric legs and a small volume.The output performance of the device is tested using a custom electrical test system.The size and thermoelectric module quantity were also optimized by finite element simulation using COMSOL software.The experimentally fabricated sector device has a volume of 33.8×11 mm2.The temperature difference is 57.8 K when a 1.5 W heat source is loaded,the output power is 247.55 nW,and the open circuit voltage is 170.21 mV.The output performance of the fan-shaped device is greatly improved compared with the device assembled by the thermoelectric ingot,the voltage is increased by 60.71%,the volume is reduced by 12.45 time,and the temperature difference is increased by about 2 times.The output power of the optimized device is nearly twice as high as that of the prototype.These results provide theoretical methods and experimental verification for the electrodeposition method to achieve isotope batteries miniaturization.In this study,bismuth telluride-based thermoelectric thin film materials were prepared based on electrodeposition method,and it was successfully applied to the miniaturization of isotope batteries.It not only realizes the miniaturization of this isotope battery,but also provides a new solution to the energy supply problem of other micro-small devices. |
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