Fabrication and Application of an Oxide Thermoelectric System

Abstract

A plate‐shaped thermoelectric module was prepared using 140 pairs of p‐type Ca3Co4O9 (Co‐349) and n‐type LaNiO3 (Ni‐113) bulks. The hot‐pressed thermoelectric oxide bulks were connected with an Ag paste, incorporating oxide powder, and Ag sheets. The module's open‐circuit voltage increases with increasing hot‐side temperature (TH) and reaches 4.5 V at a TH of 1072 K in air. No deterioration in output power was seen when power generation was carried out 10 times at a TH of 723 K with intermediate cooling to room temperature. The module was successfully used to charge a lithium‐ion battery in a mobile phone. Thermoelectric modules composed of p‐type Co‐349 and n‐type CaMnO3 (Mn‐113) bulks, which have a pipe shape, were constructed using Ag electrodes and stainless‐steel tubes. The devices were connected with the stainless‐steel tube coated with ZrO2 by thermal spray using a dielectric paste composed of silica glass and iron oxide. Power generation was carried out in flame by combustion of natural gas. Water flowed inside the stainless‐steel tube for cooling. One module consisting of 54 pairs of legs can generate 1.5 V, 0.28 W, and steam simultaneously by installing in an instantaneous water heater. Power generation was carried out four times with intermediate cooling. Deterioration in the open‐circuit voltage of the module was not observed after the fourth combustion.