An investigation of different Nd1.8Ce0.2CuO4+δ-Ce0.9Gd0.1O2-δ composite cathodes

• For the first time (100-x)Nd1.8Ce0.2CuO4±δ:(x)GDC composite system prepared by ball mill followed by sintering at 1000 °C.
• Low-frequency response of CIS attributed to non-charge transfer step of ORR is rate limiting.
• Minimum ASR for 70Nd1.8Ce0.2CuO4±δ:30GDC is due to percolation threshold.
• Superfine-crystallites with uniform grain size and shape of NCCO as well as GDC improve the overall electrochemical performance.
• 70Nd1.8Ce0.2CuO4±δ:30GDC may be potential cathode material.

The compositions of (100-x)Nd1.8Ce0.2CuO4+δ:(x)Ce0.9Gd0.1O2-δ (x = 00, 10, 20, 30, 40 and 50 vol.%) composite system, synthesized by ball milling appropriate mixture followed by sintering at 1000 °C for 4 h, are of superfine crystalline nature (crystallite size 106 to 253 nm). The dc conductivity decreases with increase in Ce0.9Gd0.1O2-δ second phase. The increase in Ce0.9Gd0.1O2-δ content in composites reduces the crystallite size of Nd1.8Ce0.2CuO4+δ. Symmetric cells in the configuration given by electrode/electrolyte/electrode with gadolinia-doped ceria (GDC) as electrolyte were fabricated by spin coating the ink of cathode. The minimum area specific resistance (ASR) value of 0.34 Ω cm2 was obtained at a temperature of 700 °C, for (70)Nd1.8Ce0.2CuO4+δ:(30)Ce0.9Gd0.1O2-δ composite cathode, and directly correlated with optimum dispersion of gadolinia-doped ceria into Nd1.8Ce0.2CuO4+δ matrix.

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