Thermoelectric properties of CaMnO$_3$ perovskite produced by spray solution combustion synthesis

CaMnO$_3$ powder was synthesized by spray solution combustion synthesis using glycine. Due to the highly exothermic reaction between the precursor components, spray solution combustion synthesis eliminates the calcination step and allows one to obtain a crystalline product in a few seconds. Consolidation was carried out using cold pressing followed by annealing in air. Single-phase CaMnO$_3$ showed a decrease in thermal conductivity relative to literature data, with the dominant mechanism of phonon scattering at grain boundaries. The mechanism of electrical conductivity is based on thermally activated small polarons hopping between localized states of Mn$^{3+}$ and Mn$^{4+}$. Synthesized CaMnO$_3$ has high absolute values of the Seebeck coefficient, which leads to competitive efficiency values among both undoped and doped compositions but eliminates the use of expensive precursors.