Carbon dioxide (CO₂) emissions have been steadily increasing since the beginning of human civilization. The greenhouse effect and climate change aroused by the cumulative CO₂ are severely impacting the global sustainable development and pose serious concerns for our future life. Strategies toward reducing the CO₂ level encompass a series of processes of carbon capture, storage, utilization, and conversion; among them the conversion of CO₂ to fuels and valuable chemicals is appealing toward the development of new sustainable technologies. As the highest oxidized form of carbon, CO₂ is thermodynamically stable. The breaking of its strong C=O double bonds is an endergonic process, which requires highly active and expensive catalysts for activation at ambient temperatures. Therefore, conversion of CO₂ with high-temperature electrolysis technologies represents a promising strategy, which is garnering increasing attention. In this study, we present a solid oxide electrolysis cell (SOECs) design for high-efficiency CO₂ conversion. The fuel electrode in an SOEC is a critical component where CO₂ reduction occurs. Therefore, we focus on the design and optimization of the fuel electrode from the perspectives of chemistry (composition) and architecture (especially the thickness) to enhance the efficiency of CO₂ electrolysis. A Ni-based cermet layer was developed as an ideal CO₂/CO fuel electrode, based on which the cell architecture was strategically optimized with prototype Ni-YSZ/YSZ/GDC/LSCF cells (YSZ: yttria-stabilized zirconia; GDC: gadolinium-doped ceria; LSCF: lanthanum strontium cobalt ferrite). Over the course of optimization, the Ni-YSZ cermet fuel electrode was methodologically fabricated with various thickness and the cells were operated at contracting temperatures. Meanwhile, the fuel was managed with different ratios of CO₂ to CO and the O₂ was supplied with different flow rates at the opposite electrode. At an exemplarily optimized condition, a high electrolysis current of 1.33 A cm^-2 was achieved at 750 ^oC with a fuel comprising of 99% CO₂ and 1% CO. To assist the cell optimization, electrochemical impedance spectroscopy (EIS) was particularly used to investigate the electrochemical properties of SOECs. Meanwhile, cell components were analyzed with scanning electron microscope (SEM) before and after the electrolysis operation to study the degradation behavior of SOECs that were operated under high-current electrolysis. The detailed cell design and experimental results will be comprehensively demonstrated and presented.