The effect of sintering additives (NiO, Co2O3, and ZnO) on the performance of barium-cerate-based solid oxide electrolysis cell (SOEC) is investigated. The performance of the SOEC with different sintering additives is determined in terms of relative density, electrochemical performance, and catalytic activity toward reverse water gas shift reaction. BaCeO3 (BC) and BaCe0.9Gd0.1O3-delta (BCG) are synthesized using conventional precipitation method, comparing to ultrasonic-assisted precipitation. The sintering additives promote both densification and grain growth. The relative density of the BCG without sintering additive is 69% while that of the BCG with 1 wt% of Co2O3, NiO and ZnO is 95%, 95% and 88%, respectively. The SEM images indicate that the BCG with sintering additives exhibits dense grains with relatively large grain size. Although the BGC with NiO and Co2O3 exhibit maximum relative density, the sample with ZnO shows relatively highest conductivity with the lowest activation energy of conduction and the sample with NiO provides the largest CO yield and CO2 conversion. The activation energy of conduction is found to be 375.41, 70.06, 66.86 and 61.80 kJ mol(-1) for BCG, BCG with 1 wt% Co2O3, NiO and ZnO, respectively. The BCG with 1 wt% NiO provides the highest CO2 conversion and CO yield at temperature below 700 degrees C (62% CO2 conversion and 32% CO yield at 700 degrees C). Temperature program of oxidation (TPO) reveals that carbon deposition can cause the low CO yield at the operating temperature above 700 degrees C.