Structural and Electrochemical Characterisation of NBZFO Cobalt-Free Cathode Material for Intermediate-Temperature Solid Oxide Fuel Cells: An Experimental Investigation

Abstract

Compared to other energy-generating technologies and energy conversion devices, intermediate-temperature solid oxide fuel cells (IT-SOFCs) have gained significant attention from energy experts due to its high energy density, moderate operating temperature (600 – 800 ℃), low emissions, and reliability. Enhancing the performance of IT-SOFCs requires suitable and excellent cathode materials. Thus, a perovskite-type Nd0.5Ba0.5Zr0.8Fe0.2O3+δ (NBZFO) material was synthesised via traditional solid-state reaction technique and analysed as a potential cathode material for IT-SOFCs. Analysis of x-ray diffraction data (XRD) revealed a single-phase perovskite material that crystallises in cubic space group (pm-3m). The thermal and electrochemical properties were analysed with the aid of thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). NBZFO has an electrical conductivity in air of 80 S/cm at 400 ℃, and a polarization resistance (PR) of 0.106 Ω∙cm2 at 800 ℃. TGA analysis reveals a slight loss in weight of about 0.58%, thereby suggesting a highly stable cathode material for IT-SOFC. Electrochemical investigation shows that NBZFO has good electronic and ionic conductivity and excellent oxygen stichometry. Further studies are required to understand the effects of varying B-site composition of the cathode material.