Promoted Performance of Layered Perovskite PrBaFe2O5+δ Cathode for Protonic Ceramic Fuel Cells by Zn Doping

Abstract

Proton-conducting solid–oxide fuel cell (H-SOFC) is an alternative promising low-temperature electrochemical cell for renewable energy, but the performance is insufficient because of the low activity of cathode materials at low temperatures. A layered perovskite oxide PrBaFe1.9Zn0.1O5+δ (PBFZ) was synthesized and investigated as a promising cathode material for low-temperature H-SOFC. Here, the partial substitution of Fe by Zn further enhances the electrical conductivity and thermal compatibility of PrBaFe2O5+δ (PBF). The PBFZ exhibits improved conductivity in the air at intermediate temperatures and good chemical compatibility with electrolytes. The oxygen vacancy formed at the PBFZ lattice due to Zn doping enhances proton defects, resulting in an improved performance by extending the catalytic sites to the whole cathode area. A single cell with a Ni-BZCY anode, PBFZ cathode, and BaZr0.7Ce0.2Y0.1O3-δ (BZCY) electrolyte membrane was successfully fabricated and tested at 550–700 °C. The maximum power density and Rp were enhanced to 513 mW·cm−2 and 0.3 Ω·cm2 at 700 °C, respectively, due to Zn doping.

Solid oxide electrolysis cells – current material development and industrial application

“…404 The crystal structure can be described as the stacking of transition metal oxide layers in between Ba oxide and lanthanide oxide layers: (BaO)-(MO x )-(LnO δ )-(MO x )-(BaO). 405–407 Through this lattice structure, two-dimensional oxygen diffusion via oxygen vacancies formed inside the three inside layers can be observed. 405 In most literature studies, praseodymium is used as the lanthanide dopant.…”

“…405–407 Through this lattice structure, two-dimensional oxygen diffusion via oxygen vacancies formed inside the three inside layers can be observed. 405 In most literature studies, praseodymium is used as the lanthanide dopant. Here, the Pr 3+ and Ba 2+ ions are ordered in alternating layers in the (001) direction.…”

“…407 Due to this structure, higher conductivities and better electrochemical performance can be obtained compared to simple perovskites. 405,407 PBFM reaches high electrical conductivities of 217 S cm −1 and 59.2 S cm −1 in air and 5% H 2 + 95% Ar at 800 °C. 407 A TEC of 11.96 × 10 −6 K −1 was measured for PBFM.…”

Progress in Developing LnBaCo2O5+δ as an Oxygen Reduction Catalyst for Solid Oxide Fuel Cells

“…Over the past few years, owing to its unique crystal structure, considerable efforts have been directed towards investigating the MIEC double perovskite oxides LnBaCo 2 O 5+δ (Ln = Lanthanide). These materials find potential applications across a multitude of domains, such as magnetism [15][16][17], SOFCs, proton-conductive ceramic fuel cells [18][19][20][21][22][23][24][25], water electrolysis [26][27][28], CO 2 electrolysis [29], chemical sensors [30][31][32], ceramic semi-permeable membranes [33][34][35], metal-air batteries [36,37], soot combustion [38], supercapacitors [39], photocatalysis [40], and solar-driven thermal storage [41,42]. Given the diverse requirements in terms of physicochemical properties for each application, this article will exclusively focus on novel strategies employed in advancing double perovskites for use as cathode catalysts in SOFCs.…”