High-performance thermoelectric calcium cobaltite nanoribbon ceramic via electrospinning and dual spark plasma texturing

High-performance polycrystalline calcium cobaltite ceramic was synthesized via electrospinning of nanoribbons, followed by dual-process compaction using spark plasma sintering and edge-free spark plasma texturing. The combination of nanoribbon electrospinning and this multistage sintering technique was employed for the first time and resulted in exceptionally well-textured thermoelectric ceramics. The textured ceramic had excellent thermoelectric properties. At 1073 K, the ceramic exhibited an electrical conductivity of 268 S cm−1 , a Seebeck coefficient of 247 µV K−1 and a heat conductivity of 3.3 W m−1 K−1 . In addition, the power factor and figure-of-merit reached enormously high values of 16.3 µW cm−1 K−2 and 0.53, respectively. This represents the highest thermoelectric performance reported to date not only for electrospun, polycrystalline calcium cobaltite fiber ceramics, but also for undoped polycrystalline calcium cobaltite ceramics.