Interfacial metal ions rearrangement of LaFe2O4-WO3 heterostructure for developing ceramic fuel cells cathode

Abstract

The development of high-performance electrochemical energy devices requires efficient oxygen redox reaction (ORR) electrocatalysts. In particular, ceramic fuel cells suffer from insufficient oxygen reduction reaction (ORR) of the cathode material at low operating temperatures. Here we report a series of three-dimensions bulk LaFe2O4-WO3 heterostructure composites synthesized by a citric acid complexing method for a solid oxide fuel cell's (SOFC) cathode material to work at lower operating temperature at 450-550 ° C. In various contents of LaFe2O4 and WO3, the 7LaFe2O4–3WO3 cathode exhibits very small area-specific-resistance (ASR) of 0.24 Ω cm2 and admirable peak power density of 625 mW-cm−2 when operating at 550 °C using Ni0.80Co0.15Al0.05LiO2-δ (NCAL) anode and Sm0.20Ce0.80O2 (SDC) electrolyte, respectively. Different characterizations such as HR-TEM, XPS, Raman, spectroscopy and calculation density functional theory (DFT) methods has been used to identifying the main reason for the improved electrochemical performance through the interface between LaFe2O4 and WO3 heterostructure in comparison of individual LaFe2O4 and WO3 structures. We have found that the LaFe2O4-WO3 heterostructure shows superficial oxygen ions release and electronic mobility which increase the overall active-sites for the enhanced ORR functionality. This aromatic approach can lead a step forward to develop desirable electrocatalysts by crosslinked interfacial properties using semiconductor-heterostructure materials for advanced energy devices.