Development of multilayer imprint process for solid oxide fuel cells

Solid oxide fuel cells (SOFCs) are fuel cells made of ceramics. To increase the SOFC energy density, we developed an SOFC with a wavy electrolyte layer. As a wavy electrolyte has a larger reaction surface area than a flat electrolyte, a higher energy density could be obtained. Our proposed process is named micro-powder imprint (μPI) with a multilayer imprint process that is useful for fabricating a microscale pattern on a ceramic sheet such as an SOFC electrolyte layer. μPI is based on nanoimprint lithography; therefore, it also exhibits the same advantages of high resolution and mass productivity. The starting material for μPI is a compound sheet containing ceramic powder and binder materials consisting of thermoplastic resin. In this study, two different sheets were stacked into one sheet as a multilayer sheet for the μPI process to form a wavy compound sheet. As the initial state of the stacked sheet, including the mechanical properties of each layer, affects the final wavy shape, we changed the material composition. As a result, the SOFCs unit cell with a wavy electrolyte was fabricated. Note that the anode layer was formed at the same time. After adding the cathode layer, we succeeded in preparing a complete cell for testing power generation.