Michael Edward Badding

Ultra-Low Mass Planar SOFC Design

This work describes our early stage efforts to develop an ultra-low mass SOFC design based on a “frit-frame” approach where sealing and framing functions are integrated. Low mass, thermal shock tolerant SOFC systems are of interest for portable power application. Small systems based on microtublar cells have shown excellent cyclability in small systems, but scaling and cost remain issues. Planar designs have shown excellent scalability. Scalable low mass SOFC systems capable of rapid thermal cycling would be of particular interest for portable applications.

Method Using Water-Based Solvent to Prepare Li7La3Zr2O12 Solid Electrolytes

Li-garnet Li7La3Zr2O12 (LLZO) is a promising candidate of solid electrolytes for high-safety solid-state Li+ ion batteries. However, because of its high reactivity to water, the preparation of LLZO powders and ceramics is not easy for large-scale amounts. Herein, a method applying water-based solvent is proposed to demonstrate a possible solution. Ta-doped LLZO, that is, Li6.4La3Zr1.4Ta0.6O12 (LLZTO), and its LLZTO/MgO composite ceramics are made by attrition milling, followed by a spray-drying process using water-based slurries. The impacts of parameters of the method on the structure and properties of green and sintered pellets are studied. A relative density of ∼95%, a Li-ion conductivity of ∼3.5 × 10-4 S/cm, and uniform grain size LLZTO/MgO garnet composite ceramics are obtained with an attrition-milled LLZTO/MgO slurry that contains 40 wt % solids and 2 wt % polyvinyl alcohol binder. Li-sulfur batteries based on these ceramics are fabricated and work under 25 °C for 20 cycles with a Coulombic efficiency of 100%. This research demonstrates a promising mass production method for the preparation of Li-garnet ceramics.