| As a feature semiconductor, thermoelectric materials can realize coupling and direct conversion between heat and electric energy, which have been used in power generation and environmental friendly refrigeration system. Simple structure, no pollution, ease of integration and miniaturization made thermoelectric power generators (TEGs) a bright future, especially for low-grade heat recovery. Ca3Co4O9+x is an ideal material for TEG, because its stability when severed under high temperature in oxygen atmosphere.Ca3Co4O9+x with different particle size were prepared by solid state reaction and sol-gel method. Based on the analysis of its synthesis mechanism, a screen printing/spin coating paste were made for Ca3Co4O9+x. By the characterization of the thick-films, an optimized thick-films fabrication process was obtained. Meanwhile, we designed and set up the thermoelectric performance test system, als the waste heat recovery system was constructed.Through all these work, the following conclusions were obtained:1. Compared to the solid state reaction, powder synthesized by sol-gel method is more applicable to thick-film fabrication.2. The conductivity of samples increased almost 100 times after cold isostatic pressing. Also, cold isostatic pressing improved the surface morphology of the films. Sample with 2 layers obtained a maximum power factor 72μW/K2m under 450℃3. The waste heat recovery system was designed and stetted up.4. We obtained the maximum output power of 0.28 W, and a power density of 29.47W/m3. |
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