La0.6Sr0.4Co0.2Fe0.8O3−δ@(Ce0.80Gd0.20)O2 nanofibre composites as oxygen electrodes for reversible solid oxide cells

Abstract

Reversible solid oxide cells (RSOCs) have the theoretical potential for achieving high energy conversion efficiencies, and for their wide application, the key lies in further increasing the current density so as to enhance hydrogen production and output power. However, the insufficient catalytic activity of the oxygen electrodes have emerged as a significant hurdle in the application of RSOCs. In this study, the La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ@(Ce_0.80Gd_0.20)O₂ nanofiber composites with reversible oxygen evolution/reduction electrocatalytic activity were successfully fabricated via electrospinning technology. Compared with the oxygen electrode materials synthesized by the traditional sol–gel method, the three-dimensional nanofiber-structured oxygen electrode described herein substantially reduces the cell polarization impedance, enhances the discharge power density and electrolytic current density, and exhibits favorable reversibility and stability in long-term tests. This work verifies the advantages of electrode morphology engineering control in expanding the catalytic interface and reaction sites.