Electrochemical and structural study of neodymium nickelate thick film deposited by spin coating on an oxyapatite electrolyte

The electrochemical characteristics of an Nd2NiO4 cathode, synthesized using the citric acid-nitrate combustion method and symmetrically deposited by spin coating on both surfaces of an La9.33Si5.3Al0.7O25.65 (LSAO) electrolyte, were studied using AC impedance spectroscopy. It was found that, varying the temperature (600 to 850 °C) and the oxygen partial pressure (0.2–10−7 atm), the impedance characteristics of the electrode could be determined by three different processes. Said processes were ionic conduction in the electrode bulk, interfacial charge transfer, and gas-phase diffusion, all of which are based on the temperature and oxygen partial pressure dependence on the polarization resistance, which is associated with each individual processes as well as on the corresponding capacitance values.