A unit cell includes an air inlet/outlet that is formed on a frame unit rather than being installed in a fuel electrode (anode) to simplify a sealing process, and accordingly, a continuous process using a tape casting technique may be performed. In addition, an electrolyte material that is in contact with an air electrode (cathode) in the frame unit is optimized to improve ion conductivity and a porosity of an upper layer material of the fuel electrode unit is optimized to increase fuel diffusion from a gas channel to an electrolyte layer. In addition, a sealing process performed inside the unit cell or between the unit cells of the stack is stabilized and strongly maintained, and thus a fuel cell using the unit cell and the stack disclosed herein may have excellent economic feasibility and high energy efficiency.
STATEMENT OF GOVERNMENT SUPPORT
 The invention was made with government support under the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant awarded by the Korean government Ministry of Knowledge Economy.