Study of strontium doped Nd2FeO4+δ cathode material for intermediate temperature solid oxide fuel cells application

Abstract

Abstract The series of Nd2–x Sr x FeO4+δ (x = 0.1 - 0.4) single phase compound is prepared with crystallite size in submicron range using combustion synthesis technique. The agglomeration of the submicron sized crystallites resulted into formation of porous electrode layer is realized from scanning electron microscopy. The dcconductivity results showed maximum σ for x = 0.2, which also exhibited minimum activation energy. The comparative low dc conductivity with literature reports is due to high porosity as obtained from agglomerated submicron crystallites. Variation in conductivity in Nd2–x Sr x FeO4+δ is Sr-dependent and understood f rom defect chemistry. The complex impedance plots of the symmetric cell showed decrease in the real axis intercept with increased temperature in turn reduced area specific resistance (ASR). Nd1.8Sr0.2FeO4+δ cathode exhibits lowest ASR (= 1.92±0.015 Ohm cm2) at 973 K. The oxygen partial pressure dependent ASR indicated that the charge transfer at electrode-electrolyte interface is the rate limiting factor while oxygen reduction reaction (ORR).