Effect of improved sol-gel method on composition and micro morphology of Ca

Ca3Co4O9 is a potential high temperature thermoelectric material. We explore the hydrothermal treatment improved sol-gel method to prepare Ca3Co4O9 thermoelectric materials. We find that this treatment can increase the thermoelectric performance of the samples compared with the conventional citric acid sol-gel method. We also find the samples prepared by the improved sol-gel method have more uniform grain distribution, better densification, and less voids. At about 1000K, compared with the conventional sol-gel method, the power factor of the samples prepared by improved sol-gel method improves about 168%