Nanostructured GDC-impregnated La 0.7Ca 0.3CrO 3−δ symmetrical electrodes for solid oxide fuel cells operating on hydrogen and city gas

Abstract

Nanostructured Gd 0.1Ce 0.9O 1.95 (GDC)-impregnated La 0.7Ca 0.3CrO 3−δ (LCC) composites were investigated as symmetrical electrodes for La 0.9Sr 0.1Ga 0.8Mg 0.2O 3−δ (LSGM)-supported solid oxide fuel cells (SOFCs) without using interlayer at anode/electrolyte interface. The impregnation of aqueous Gd 0.1Ce 0.9(NO 3) x solution into the porous LCC electrode backbones was found to form nanosized GDC particles on LCC surfaces after calcining at 850 °C for 30 min. The optimized performance of electrodes for SOFCs had been achieved through the impregnation cycles of 3–7 times. The introduction of the ion conducting phase GDC in nanometer significantly enhanced the symmetrical electrode performance. The symmetrical cell with the impregnation of five times displayed the best performance and the maximum power densities were 521 mW cm −2 and 638 mW cm −2 at 850 °C and 900 °C with dry H 2 as fuel, respectively. Using commercial city gas containing H 2S as fuel, the maximum power densities of the cell reached 362 mW cm −2 and 491 mW cm −2 at 850 °C and 900 °C, respectively. The microstructure, valence state of Ce element and electrochemical stability of the nanostructured GDC-impregnated LCC composites were also discussed.