The Effect of Plasma Spraying Power on La₀.₅₈Sr₀.₄Co₀.₂Fe₀.₈O₃₋δ–La₀.₈Sr₀.₂Ga₀.₈Mg₀.₂O₃₋δComposite Cathode Interlayer Microstructure and Cell Performance

Abstract

Abstract The metal‐supported intermediate temperature solid oxide fuel cells with a porous nickel substrate, a nano‐structured LDC (Ce 0.55 La 0.45 O 2–δ )–Ni composite anode, an LDC diffusion barrier layer, an LSGM (La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3–δ ) electrolyte, an LSCF (La 0.58 Sr 0.4 Co 0.2 Fe 0.8 O 3–δ )–LSGM composite cathode interlayer and an LSCF cathode current collector are fabricated by atmospheric plasma spraying. Four different plasma spraying powers of 26, 28, 30, and 34 kW are used to fabricate the LSCF–LSGM composite cathode interlayers. Each cell with a prepared LSCF–LSGM composite cathode interlayer has been post‐heat treated at 960 °C for 2 h in air with an applied pressure of 450 g cm –2 . The current‐voltage‐power and AC impedance measurements indicate that the LSCF–LSGM composite cathode interlayer formed at 28 kW plasma spraying power has the best power performance and the smallest polarization resistance at temperatures from 600 to 800 °C. The microstructure of the LSCF–LSGM composite cathode interlayer shows to be less dense and composed of smaller dense regions as the plasma spraying power decreases to 28 kW. The durability test of the cell with an optimized LSCF–LSGM composite cathode interlayer gives a degradation rate of 1.1% kh –1 at the 0.3 A cm –2 constant current density and 750 °C test temperature.

Key findings

• ▸The LSCF–LSGM composite cathode interlayer formed at 28 kW plasma spraying power had the best power performance.
• ▸The current–voltage–power and AC impedance measurements indicate that the cell performance is affected by the plasma spraying power.
• ▸The post-heat treatment at 960 °C for 2 h in air with an applied pressure of 450 g cm⁻² did not significantly affect the cell performance.

Keywords

Identifiers

DOI

10.1002/fuce.201300143

Journal

Fuel Cells

Year

2013