Sinteractive anodic powders improve densification and electrochemical properties of BaZr0.8Y0.2O3−δ electrolyte films for anode-supported solid oxidefuel cells

Abstract

The difficult sintering of BaZr_0.8Y_0.2O_3−δ (BZY20) powders makes the fabrication of anode-supported BZY20 electrolyte films complex. Dense BZY20 membranes were successfully fabricated on anode substrates made of sinteractive NiO-BZY20 powders, prepared by a combustion method. With respect to traditional anode substrates made of powders prepared by mechanical mixing, the anode substrates made of the wet-chemically synthesized composite NiO–BZY20 powders significantly promoted the densification of BZY20 membranes: dense BZY20 films were obtained after co-pressing and co-firing at 1300 °C, a much lower temperature than those usually needed for densifying BZY20 membranes. Improved electrochemical performance was also observed: the supported BZY20 films maintained a high proton conductivity, up to 5.4 × 10⁻³ S cm⁻¹ at 700 °C. Moreover, an anode-supported fuel cell with a 30 µm thick BZY20 electrolyte film fabricated at 1400 °C on the anode made of the wet-chemically synthesized NiO–BZY20 powder showed a peak power density of 172 mW cm⁻² at 700 °C, using La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ–BaZr_0.7Y_0.2Pr_0.1O_3−δ as the cathode material, with a remarkable performance for proton-conducting solid oxide fuel cell (SOFC) applications.