Mn1.1Co1.5Fe0.4O4 ceramics with tailored sintering temperature, microstructure, and NTCR characteristics were prepared using Bi2O3 sintering additive by a solid-state reaction route. Densification and morphological characterization indicate that bismuth trioxide can play a critical role in the sintering process. The results reveal that the sintering temperature can be decreased significantly from 1200 degrees C to 1050 degrees C by using the appropriate content of Bi2O3 additive. The resistivity decreases first and then increases with increasing Bi2O3 content. The obtained B-25/50 value and rho(25) ranges were 3647-3697 K, and 800-1075 omega cm, respectively. Oxygen sorption theory can be used to illustrate the optimal thermal stability (Delta R/R-0 = 0.10%). Complex impedance analysis further elucidates that grain boundaries make a dominant contribution to the total resistance. The mechanisms of grain boundary conduction and relaxation behavior are systematically analyzed. These findings open up a window for the further advancement of NTC ceramics at lower sintering temperature.