Tubular thermoelectric module based on oxide elements grown by the laser floating zone

• Autor(a) principal: Merkulov, O. V.
• Data de Publicação: 2021
• Outros Autores: Lopes, D., Markov, A. A., Ferreira, N. M., Patrakeev, M. V., Kovalevsky, A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/34560
• topic: Electrical conductivity; lfz; Oxide thermoelectrics; Seebeck coefficient; Thermoelectric module

This work seeks possibilities for advancing the thermoelectric oxide technology by exploring a module design involving materials produced by laser processing. A tubular thermoelectric generator of modular construction with functional elements located parallel to a pipe-shaped heat source was designed and manufactured. The p- and n-type counterparts based on Ca3Co4O9 and Ca0.95Pr0.05MnO3 were grown by the laser floating zone (LFZ) technique, ensuring highly dense microstructures and giving the unique possibility for fast and crucible-free processing of the legs with desirable geometry. The detailed structural and microstructural characterization indicated that the LFZ processing should be accompanied with an additional thermal annealing step to equilibrate the phase composition. Although the measured electrical performance was found close to or slightly higher compared to that of similar materials produced by other routes, it was still notably suppressed by the remaining phase impurities affecting the module's output. The maximum observed power output of the module containing 12 Ca3Co4O9/Ca0.95Pr0.05MnO3 thermoelectric couples reached up to 20 mW at a temperature gradient of 389 °C and a hot side temperature of 525 °C. The contribution of various factors to the overall performance was analyzed. The results suggest that the power output could be significantly enhanced by decreasing the contact resistance at the cold side and proper optimization of the LFZ processing conditions.