Fe2O3 as an economic dopant for 8YSZ electrolytes can indeed improve the oxygen ion transport ability in the middle working temperature. Based upon this research, using 4% Fe2O3 to be a dopant for 8YSZ has the highest oxygen ion conductivity. Also, no matter doping Fe2O3 into 8YSZ or not, temperature effect can truly influence electrolyte’s oxygen transport. Display omitted The present work investigates Fe2O3 doping as a method of improving the oxygen ion conductivity (OIC) of electrolytes in solid oxide fuel cells (SOFCs) working in a temperature range between 773 K and 973 K. Yttria-stabilised zirconia (YSZ), which alone does not have an OIC sufficiently high for working in the specified temperature range, is used as the electrolyte in the present work. A molecular dynamics (MD) modelling approach is employed to simulate the electrolyte, and the oxygen ion conductivity is characterised and examined for a range of doping proportions and working temperatures. Modelling results indicate that there exists an upper limit of oxygen vacancy concentration for doped 8YSZ electrolytes, and that the optimum OIC is achieved by an 8YSZ electrolyte doped with approximately 4% Fe2O3. Also reported are several other findings that might be of interest to future studies on the performance of electrolytes.