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

Abstract 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.