## 4 Conclusions  
In this study, the characteristics of an SOFC unit were tested using a numerical simulation method. This work examined the influence of the electrolyte porosity and hydrogen concentration on the operation of the cell. The results indicate that the performance of the fuel cell is highly dependent on the structural characteristics of the electrolyte layer, such as its porosity and dimensions. The distribution of H\({}_{2}\) in the anode due to different levels of internal porosity imposes a limitation on the concentration of mass reacting in the SOFC. A higher porosity of the electrode can enhance fuel mass transfer. A simulation was performed to determine the molar concentration of hydrogen in the electrolyte layer of an SOFC operating at 650 \({}^{\circ}\)C. The highest molar concentration value was 0.85, but it mostly ranged from 0.55 to 0.75 because of the influence of the electrochemical reaction in the fuel cell, which caused the molar concentration of H\({}_{2}\) in the electrolyte layer to gradually increase and peak at 0.85. Additionally, the influence of operating temperature on the SOFC's performance was surveyed. The results show an increase in the chemical reaction rate and hydrogen concentration as the operating temperature rises. The simulation results reveal that the highest potential difference of the cell is 0.954 V, while the experimental results indicate that the highest potential difference of the cell is 0.983 V at an operating temperature of 650 \({}^{\circ}\)C. The highest current density from the simulation results is 350 mA\(\cdot\)cm\({}^{-2}\), and that from the experimental results is 375 mA\(\cdot\)cm\({}^{-2}\). For an SOFC operating at 700 \({}^{\circ}\)C, the simulation results show that the highest current and voltage densities are 456.05 mA\(\cdot\)cm\({}^{-2}\) and 0.985 V, respectively. Meanwhile, the experimental results show that the highest current and voltage of the cell are 481.25 mA\(\cdot\)cm\({}^{-2}\) and 1.07 V, respectively. At the operating temperature of 750 \({}^{\circ}\)C, it can be seen from the simulation results that the highest current and voltage of the SOFC are 579.08 mA\(\cdot\)cm\({}^{-2}\) and 1.044 V, respectively. The experimental results show that the highest current and voltage of the cell are 587.4 mA\(\cdot\)cm\({}^{-2}\) and 1.12 V, respectively. The results also indicate that the operating temperature has a significant influence on the electrochemical reactions and conductivity of electric charges. This has a remarkable impact on the performance of the SOFC. The effects of the flow rate and operating pressure in the model, as well as the impact of the SOFC's shape on the cell's performance, will be investigated in future studies.  
This research received no external funding.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The raw data supporting the conclusions of this article will be made available by the authors on request.  
**Acknowledgments:** The author gratefully thanks the Ho Chi Minh City University of Technology and Education for the support provided by the Project No. T2024-44.