Electrochemical characterization of B-site cation-excess Pr2Ni0.75Cu0.25Ga0.05O4+δ cathode for IT-SOFCs

Abstract

characterization of B-site cation-excess Pr 2 Ni 0.75 Cu 0.25 Ga 0.05 O 4 þ δ cathode for ITSOFCs, Ceramics International, http://dx.Abstract The B-site cation-excess K 2 NiF 4 -type structure oxide, Pr 2 Ni 0.75 Cu 0.25 Ga 0.05 O 4+δ (PNCG) is investigated as a cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). XRD result shows that PNCG cathode is chemically compatible with the electrolyte Gd 0.1 Ce 0.9 O 2−δ (GDC) at 900 o C for 5 h. The PNCG material exhibits a (Y. Ji). 2 semiconductor to metal transition around 425 o C. The thermal expansion coefficient (TEC) of the PNCG sample is 12.72×10 −6 K −1 between 30 and 850 o C in air. The polarization resistance (R p ) of PNCG cathode on GDC electrolyte is 0.105, 0.197 and 0.300 Ω cm 2 at 800, 750, 700 °C, respectively. A maximum power density of 371 mW cm −2 is obtained at 800 °C for single-cell with 300 µm thick GDC electrolyte and PNCG cathode. The results of this study demonstrate that PNCG can be a promising cathode material for IT-SOFCs.

Oxygen transport in Pr nickelates: Elucidation of atomic-scale features

“…Pr 2 NiO 4+δ oxide with a layered Ruddlesden-Popper (R-P) structure is a promising material for SOFC cathodes [1][2][3][4][5][6][7][8], electrodes for electrolysers and reversible cells [9,10] and oxygen separation membranes [11][12][13][14] due to a high oxygen mobility provided by the cooperative mechanism of oxygen migration involving both interstitial oxygen species and apical oxygen of the NiO 6 octahedra, as well as intermediate values of thermal expansion coefficients (TECs) and stability to carbonization [3,5,11,[15][16][17][18][19][20]. Doping is usually applied to diminish Pr 2 NiO 4+δ phase instability in the temperature range of 850-1000°C [21].…”