The electrochemical properties of bi-layered electrolytes GDC(Gd0.1Ce0.9O1.95)/YSZ(Y0.16Zr0.84O1.92), ESB(Er0.4Bi1.6O3)/GDC and ESB/YSZ with different layer thickness fractions in the temperature range from 400 to 800 degrees C have been investigated by simulating calculations based on a charge transport continuity equation and the characteristic conductivity parameters of YSZ, GDC and ESB. It has been found that the model cells with ESB/GDC and ESB/YSZ bi-layered electrolytes can render a higher maximum power density that increases with the ESB layer thickness than those with GDC/YSZ bi-layered electrolytes in the studied temperature range. While the oxygen partial pressure at the interface of ESB/GDC is much lower than that of ESB/YSZ electrolyte with the same ESB thickness fraction, a higher interfacial oxygen partial pressure than the critical decomposition value of Bi2O3 can be achieved in the ESB/YSZ electrolytes even with small YSZ thickness fractions. This result strongly suggests that the ESB/YSZ, instead of ESB/GDC, would be a thermodynamic stable bi-layered electrolyte with high output power density for potential applications in the intermediate to low temperature SOFCs. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.