Development of Al_2O_3-ZnO/Ca_3Co_4O_9 Module for Thermoelectric Power Generation

摘要

Pure and Al_2O_3 (2%, 5%, 8%) doped sintered ZnO (n-type) and pure sintered Ca_3Co_4O_9 (p-type) pellets were prepared by conventional solid state synthesis starting from the oxides. The sintered pellets were cut by a diamond saw in a pillar shape (15mm×5mm×5mm) for physical properties measurements. The best doped sample was 2% Al_2O_3 ZnO showing Seebeck coefficient S=-180mV/K and electrical conductivity σ=8S/cm at 400°C, while thermal conductivity κ=1.8W/m×K at 600°C. Typical values for Ca_3Co_4O_9 were S=82.5mV/K and σ=125S/cm at 800°C, while κ=1.01W/m×K at 600°C.Several modules fabricated by elements cut from sintered pellets were tested and the best performance was obtained in the module formed by six 2% Al_2O_3-ZnO/Ca_3Co_4O_9 couples, that generated an output power P=3.7×10~(-5)W at 500°C (when △T=260°C).