Engineered anode structure for enhanced electrochemical performance of anode-supported planar solid oxide fuel cell

A novel approach of fabricating SOFC anode comprising graded compositions in constituent phases having layer wise microstructural variation is reported. Such anode encompasses conventional NiO–YSZ (40 vol% Ni) with higher porosity at the fuel inlet side and Ni–YSZ electroless cermet (28–32 vol% Ni) with less porosity toward the electrolyte. Microstructures and thicknesses of the bilayer anodes (BLA) are varied sequentially from 50 to 250 μm for better thermal compatibility and cell performance. Significant augmentation in performance (3.5 A cm−2 at 800 °C, 0.7 V) is obtained with engineered trilayer anode (TLA) having conventional anode support in conjunction with layers of electroless cermet each of 50 μm having 28 and 32 vol% Ni. Engineered TLA accounts for substantial reduction both in cell polarization (ohmic ASR: 78 mΩ cm2 versus 2835 mΩ cm2; cell impedance: 0.35 Ω cm2 versus 0.9 Ω cm2) and degradation rate (76 μV h−1 versus 219 μV h−1) compared to cells fabricated with conventional cermet.

► Layered SOFC anodes having functionally graded microstructures are fabricated.
► Anodes are engineered using a novel electroless cermet having variable thickness.
► Bi/tri-layer anodes are fabricated with layer wise variation of constituent phases.
► Graded trilayer anode augments the cell performance to 3.5 A cm−2 at 800 °C and 0.7 V.
► Such cell reduces polarization to 0.35 Ω cm2 (ASR 78 mΩ cm2) & degradation to 76 μV h−1.