Enhanced Thermoelectric Performance of La1.98Sr0.02Cu0.94Co0.06O4 by Multiwalled Carbon Nanotubes Addition

Abstract

Effect of multiwalled carbon nanotubes (MWCNTs) addition on thermoelectric properties of polycrystalline LSCCO (La_1.98Sr_0.02Cu_0.94Co_0.06O₄) has been examined. The samples have been synthesized via the solid-state reaction technique. Micro-structural and surface morphology of the synthesized pellets have been investigated using X-ray diffraction and Field Emission Scanning Electron Microscopy, respectively. The electrical resistivity and Seebeck coefficient of investigated pellets have been measured using a custom-built apparatus between 300 and 450 K. Nevertheless, the transient heat transfer technique has been adopted for thermal conductivity measurement. The addition of MWCNTs significantly enhances the electrical conductivity and reduces the thermal conductivity of LSCCO. This results in a remarkable improvement in the figure of merit in spite of the reduction in Seebeck coefficient with MWCNTs addition. The maximum ZT value ~0.07 is achieved at 323 K for 0.05 wt% MWCNTs-loaded LSCCO, which is ~28 times that of pristine LSCCO. The enhanced thermoelectric performance is attributed to the increased carrier concentration, reduced grain size, and improved interface phonon scattering due to MWCNTs addition. Our results demonstrate the potential of MWCNTs as an effective additive to enhance the thermoelectric properties of LSCCO-based materials.