Validation of Nd_2NiO_(4+δ) as Oxygen Electrode Material for Intermediate Temperature Solid Oxide Cells with LSGM Electrolyte

摘要

The oxygen reduction reaction (ORR) was studied by Electrochemical Impedance Spectroscopy (EIS) for Nd_2NiO_(4+δ) (NNO) electrodes deposited on La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(2.85) (LSGM) electrolyte. The influence of NNO microstructure on the electrochemical performance was evaluated. The EIS measurements were carried out as a function of temperature (500＜T＜750°C) and oxygen partial pressure (10~(-4)＜pO_2＜1atm). Three contributions associated with the ORR were identified: at high (HF), medium (MF) and low frequencies (LF). The HF contribution was associated with oxygen ion transfer trough electrode/electrolyte interphase. The MF contribution was attributed to oxygen ions diffusion within the NNO. The LF contribution was related to O_2-dissociative adsorption for NNO obtained by chemical routes, where the particle sizes are smaller. If NNO were obtained by Solid State Reaction, the LF element was associated with a convolution of dissociative adsorption and gas diffusion processes.