Multi-scale parallel and texture interface to enhance thermoelectric performance of p-type Ca3Co4O9 semiconductor materials

Abstract

Ca3Co4O9 is considered as an attractive material for high-temperature area application. The correlation between structure modulation and electric-thermal transport properties is an important prerequisite to optimize thermoelectric performance of Ca3Co4O9 materials. p-type Ca3Co4O9-based ceramics with texture interface were successfully prepared by tape casting method. The different content of template seeds was added into the Ca3Co4O9 semiconductor, successfully constructing the parallel interfaces. The “brick-wall” structure was formed due to the liquid film existed at grain boundaries. The sample with 15 wt% template seeds additives yielded ∼60 % rise in power factor with a peak value of 0.33 mW/(m·K2), and the low thermal conductivity of 0.97 W/(m·K) was obtained at 800 ℃. Additionally, the ZT value reached 0.34 due to the presence of multi-scale parallel interfaces among the stripe-like grains, which effectively scattered the long-wave, middle-wave and short-wave phonons and strengthened the charge carrier transporting. This texturing method offered a meaningful way for enhancing thermoelectric properties of oxides thermoelectric materials.