Achieving enhanced thermoelectric performance of Ca1−x−yLaxSryMnO3 via synergistic carrier concentration optimization and chemical bond engineering

Abstract In this work, we fabricate perovskite-type Ca1-x-yLaxSryMnO3 thermoelectric materials using co-precipitation method, followed by cold pressing and hot sintering. The La/Sr dual doping modifies chemical composition and bonding properties of CaMnO3, resulting in improved electrical transport properties with tunable carrier concentration, carrier mobility and effective mass. Meanwhile, the phonon transport properties are also influenced, reflected by the reduced lattice thermal conductivity of Ca1-x-yLaxSryMnO3. As a result, Ca0.94La0.02Sr0.04MnO3 shows significantly enhanced power factor up to 374 μW·m-1·K-2 and figure of merit up to ∼0.22 at 973 K, which is ∼144% higher than those of pristine CaMnO3. This study rationalizes a potential strategy to improve the thermoelectric performance of CaMnO3-based materials.