In-filled Skutterudite-Based Thermoelectric Power Generation Module with High Durability in Air for Evaluation of Power Generation Performance

There is a need to develop a skutterudite-based thermoelectric power generation module that can be used stably for long periods in high-temperature atmosphere, but the durability of p-type skutterudite compounds is generally lower than that of n-type skutterudite compounds in a high-temperature atmosphere. Thus, a thermoelectric generation module consisting of 14 pairs of p-type In_0.25Co₃FeSb₁₂ with an InSb layer formed on the surface and n-type In_0.25Co_3.88Ni_0.12Sb₁₂ has been fabricated using Ag sheets as electrodes and metal paste as bonding material. When the temperatures at the cold side and the hot side of the module were kept at 293 K and 773 K, respectively, a maximum power density of 2.46 kW m⁻² was obtained. During a long period of operation of 500 h in the air, with an increase in the elapsed time, the electric resistance of the module increased slightly, while the maximum electric power tended to decrease. The reduction in the maximum electric power of the module during continuous operation was estimated to be approximately 2%. On the other hand, for a module using p-type In_0.25Co₃FeSb₁₂ device material with no InSb layer formed on the surface, an 8% increase in the electrical resistance and a 12% decrease in the maximum electric power were observed after operation for 170 h in the air. This result indicates that the InSb layer formed on the surface of the p-type In_0.25Co₃FeSb₁₂ device material can significantly improve the durability of the module in the air at high temperature.