Novel sr-doped NdMn0.5Cr0.5O3-δ electrodes for symmetrical solid oxide fuel cell

Abstract

Solid oxide fuel cells (SOFCs) have emerged as promising energy conversion devices, offering high efficiency and environmental sustainability. Efficient electrode materials are crucial for the overall cell performance of SOFCs. Perovskite type Nd_1-xSr_xMn_0.5Cr_0.5O_3-δ (x = 0.25, 0.5) (NSCM25, NSCM50) was synthesized via conventional solid-state reaction technique. Structural, thermal and electrochemical characterizations were performed using X-ray diffraction, thermogravimetric analysis, conductivity measurements, scanning electron microscope, thermal expansion coefficient analysis and impedance spectroscopy. Structural analysis revealed that both compositions exhibit orthorhombic symmetry in the Pbnm space group. Thermogravimetric analysis (TGA) indicated minimal weight changes in both pre-reduced and as-prepared samples. The electrical conductivities in air at 600 ℃ were found to be 1.69 S/cm for NSCM25 and 4.91 S/cm for NSCM50, with a decrease observed under reduced oxygen partial pressure. Polarization resistance (R_p) analysis was conducted on symmetrical cells composed of NSCM25|GDC|NSCM25, NSCM50|GDC|NSCM50, NSCM25|YSZ|NSCM25, and NSCM50|YSZ|NSCM50. At 900 ℃, the polarization resistances were 0.12 Ωcm², 0.21 Ωcm², 0.11 Ωcm², and 0.67 Ωcm², respectively. The results suggest that NSCM25 and NSCM50 hold promise as electrode materials for symmetrical solid oxide fuel cells (SSOFC) employing YSZ or GDC electrolyte.