Effects of Neodymium doping on oxygen reduction activity in Pr2-xNdxNiO4+d cathodes

ALBERTO CANEIRO; ALEJANDRA MONTENEGRO HERNÁNDEZ; LILIANA MOGNI; JESUS VEGA CASTILLO

PyeongChang

Conferencia; 22nd International Conference on Solid State Ionics (SSI-22); 2019

Ln2NiO4+d oxides with K2NiF4-type structure are considered to be some of the most attractive electrodes for Solid oxide fuel cells (SOFC) application [1], they have low thermal expansion coefficient values and high surface exchange and oxygen diffusion coefficients. Their crystal structure consists of LnNiO3 perovskite layers stacked alternating with rock salt LnO layers. Some authors have reported a promising performance of Ln2NiO4+d (Ln: La, Pr and Nd) as oxygen reduction electrodes, especially for Ln=Pr [2]. Nevertheless, other studies show that Pr2NiO4+d (PNO) is not thermally stable at temperatures below 900 ºC and tends to segregate secondary phases that harm its electrochemical properties [3]. Nd2NiO4+d (NNO) instead, shows thermal stability and chemical compatibility with a few electrolyte materials, below 900 ºC [4]. Aiming to combine the good electrochemical features of PNO with the thermal stability and chemical compatibility of NNO, solid solutions between PNO and NNO such as Nd2-xPrxNiO4+d (NPNO, x=0.3, 1 and 1.7) were studied. NPNO are prepared successfully by HMTA method. The effects of praseodymium doping on the crystal structure, the oxygen non-stoichiometry, and the cathode properties are evaluated by XRD, SEM, DTA, TGA and EIS.