Oxygen solubility is the rate-determining step (RDS) for the reduction reaction on the cathodes of molten carbonate fuel cells (MCFCs), especially at low operating temperatures below 600 degrees C. The poor wetting property of the mixed ionic and electronic conductor (MIEC) coating, such as BYS (Bi1.5Y0.3Sm0.2O3-delta) on the NiO cathode, to the liquid electrolyte creates openings where oxygen absorption and dissociation take place to provide more oxide ionic species to electrochemical reaction sites (ERSs). Therefore, poor wetting MIEC-coated cells showed a much higher power density compared to standard cells, with a factor of 1.4 at the low operating temperature of 550 degrees C. Long-term operation of 2500 hours with a low voltage loss of 9 mV suggests that BYS is a promising alternative cathode material for molten carbonate fuel cells. (C) The Author(s) 2014. Published by ECS. All rights reserved.