Structural and electrochemical properties of B-site Ru-doped (La0.8Sr0.2)0.9Sc0.2Mn0.8O3-δ as symmetrical electrodes for reversible solid oxide cells

Abstract

Reversible solid oxide cells could be energy transfer devices between electrical power and hydrogen energy due to their multi-functions, such as fuel cells and electrolysis cells. However, the traditional configuration of solid oxide cells induces the thermal mismatch among different components during the changing between different operating modes. Herein, we demonstrate that A-site deficient (La0.8Sr0.2)0.9Sc0.2Mn0.8-xRuxO3–δ can be used as an air electrode and a fuel electrode simultaneously in reversible solid oxide cells. Ruthenium nanoparticle catalysts are exsolved on the surface of (La0.8Sr0.2)0.9Sc0.2Mn0.8-xRuxO3–δ in the reducing atmosphere. The electronic conductivity in air and 5% H2/N2 are optimized via the substitution of manganese by ruthenium, which changes the distortion of BO6 octahedron and the integral overlap between d orbitals of B-site atoms and O-p orbitals. The electrochemical activity of air electrode and fuel electrode are significantly improved simultaneously after Ru-doing. In fuel cell mode, the maximum power density of the symmetrical single cell reaches 318 mW cm−2 at 800 °C. In electrolysis cell mode, the electrolysis current density is 0.536 A cm−2 at 750 °C with an applied voltage of 1.5 V at 50% H2O/H2. The synthesized (La0.8Sr0.2)0.9Sc0.2Mn0.8-xRuxO3–δ material is a promising symmetrical electrode for reversible solid oxide cells.