## 3 Results and Discussion
### Comparison of Simulation and Experimental Results at Different Temperatures  
Figure 9 shows the simulation and experimental results for an SOFC at operating temperatures of 650, 700, and 750 \({}^{\circ}\)C. The SOFC models used in the simulation and experiment were the same. The modeling dimensions of the unit cell were as follows: the thicknesses of the hydrogen electrode, electrolyte, and oxygen electrode layers were 540, 18, and 25 \(\upmu\)m, respectively. The simulation results in Figure 9a show that the largest potential difference of the cell was 0.954 V, while the experimental results show that the largest potential difference was 0.983 V, and the smallest experimental value was 0.17 V compared with 0.06 V from the simulation results. The highest current density from the simulation results was 350 mA\(\cdot\)cm\({}^{-2}\), while the experimental result was 375 mA\(\cdot\)cm\({}^{-2}\). Figure 9b and 9c show the performance of the SOFC operating at 700 and 750 \({}^{\circ}\)C. For the SOFC operating at 700 \({}^{\circ}\)C (Figure 9b), the simulation results show that the highest current density and voltage were 456.05 mA\(\cdot\)cm\({}^{-2}\) and 0.985 V, respectively. Meanwhile, the experimental results reveal that the highest current and voltage of the cell were 481.25 mA\(\cdot\)cm\({}^{-2}\) and 1.07 V, respectively. Figure 9c shows the performance of the SOFC operating at 750 \({}^{\circ}\)C. It can be seen from the simulation results that the highest current and voltage of the SOFC were 579.08 mA\(\cdot\)cm\({}^{-2}\) and 1.044 V, respectively. Meanwhile, the experimental results reveal that the highest current and voltage of the cell were 587.4 mA\(\cdot\)cm\({}^{-2}\) and 1.12 V, respectively. Figure 9 displays the discrepancy between the experimental and simulation results for an SOFC operating at different temperatures. However, the difference is minimal and conforms to theory. The results also show that when the SOFC was operating at high temperatures, the differences in the current and voltage density between the simulation and experiment were smaller. This happened because SOFC electrolysis accelerates due to rapid electrochemical reactions at higher temperatures.  
Figure 8: Comparison of the current density and voltage at different temperatures.  
Figure 9: Comparison of simulation and experimental results for the SOFC at operating temperatures of (**a**) 650 \({}^{\circ}\)C, (**b**) 700 \({}^{\circ}\)C, and (**c**) 750 \({}^{\circ}\)C.  
As shown in the figure, the simulation performance curves show slight differences compared to the experimental data. This occurred because the experimental tests were conducted in a much shorter time than the simulation model. The iteration step in the experiment tests is also much shorter than in the simulation. In addition, determining the key parameters from the experimental tests is difficult. Moreover, the error of the testing machine for current density is about 5%. It can be seen that the power density of the homemade cell is far below the state-of-art in SOFC technology, possibly due to inconsistent cells fabricated manually in the lab. Cell performance depends on the cell fabrication skill. In this work, commercial materials were used to manually manufacture the cells, and achieving consistency in cell performance remains a challenge.