Cobalt substituted Lanthanide Nickelates (Ln_2Ni_(1-x)Co_xO_(4+δ), Ln = La, Pr; x = 0, 0.1, 0.2) as High Performance Oxygen Electrodes for Solid Oxide Cells

摘要

The present study is focused on the development of alternative oxygen electrodes for Solid Oxide Fuel Cells (SOFCs) and Solid Oxide Electrolyzers Cells (SOECs). Rare earth nickelates with general formula Ln_2NiO_(4+δ) (Ln = La, Pr or Nd) have shown good performance as oxygen electrodes with various electrolytes. To further enhance the physico-chemical properties, electrochemical performance as oxygen electrode and durability of Solid Oxide Cells (SOCs), herein, we have performed the substitution of nickel with cobalt in these nickelates. Two compositions (x=0.1 and 0.2) were mainly considered and completely characterized using several techniques. The single cells were then prepared and electrochemically characterized using DC- and AC-techniques in the temperature range 700-900°C. The durability test up to 250h were also investigated at 1 A.cm~(-2) current density at 800°C under both SOFC (dry conditions) and SOEC conditions (with 50% H_2 and 50% H_2O feed gas mixture) indicating different degradation behavior.