Energy devices in modern society require high efficiency, carbon neutrality, and the capability of distributed power generation. A fuel cell is an energy conversion device, that satisfies all of these requirements. However, most fuel cells use hydrogen as a fuel, and more than half of hydrogen is currently produced through hydrocarbon reforming, resulting in significant energy loss. Additionally, the storage and supply of hydrogen require costly systems, and a large amount of energy is consumed during compression or liquidation processes. This paper develops a solid oxide fuel cell, that uses hydrocarbon directly as fuel to resolve this problem. A small amount of Ru is mixed with the Ni-based electrode, for the effective internal reforming of hydrocarbons. For rapid deposition of YSZ electrolytes, we developed a reactive sputtering process, using a DC power source. The developed thin-film solid oxide fuel cell, showed a performance of 76 mW/cm² at 500℃ using methane as fuel.

Thin film solid oxide fuel cells (TF-SOFCs) are considered to be a promising next generation energy conversion device. TFSOFCs have many advantages such as rapid turn-on and off, fuel flexibility, material flexibility, high power density and availability of compact system. Electrodes and electrolytes of TF-SOFCs are fabricated by thin film processes. In order to fabricate high performance TF-SOFCs, proper thin film processes have to be used due to the unique requirements of each part of the TF-SOFCs. This paper reviews the thin film deposition process for fabrication of TF-SOFCs and the advantages and disadvantages of physical and chemical vapor deposition processes. In addition, materials prepared through thin film processes and the performance results of TF-SOFCs are reviewed.