High-rate lithium cycling in a scalable trilayer Li-garnet-electrolyte architecture

Abstract Solid-state lithium batteries promise to exceed the capabilities of traditional Li-ion batteries in safety and performance. However, a number of obstacles have stood in the path of solid-state battery development, primarily high resistance and low capacity. In this work, these barriers are overcome through the fabrication of a uniquely microstructured solid electrolyte architecture based on a doped Li 7 La 3 Zr 2 O 12 (LLZ) ceramic Li-conductor. Specifically, a porous-dense-porous trilayer structure was fabricated by tape casting, a scalable roll-to-roll manufacturing technique. The dense (>99%) center layer can be fabricated as thin as ∼10 μm and blocks dendrites over hundreds of cycles. The microstructured porous layers serve as electrode supports and increase the mechanical strength by ∼9×, making the cells strong enough to handle with ease. Additionally, the porous layers multiply the electrode–electrolyte interfacial surface area by >40× compared to a typical planar interface. Lithium symmetric cells based on the trilayer architecture were cycled at room temperature and achieved area-specific resistances (∼7 Ω-cm 2 ) dramatically lower, and current densities dramatically higher (10 mA/cm 2 ), than previously reported literature results. Moreover, to demonstrate scalability a large-format cell was fabricated with lithium metal in one porous layer and a sulfur electrode with conductive carbon and an ionic liquid interface in the other, achieving 1244 mAh/g S utilization and 195 Wh/kg based on total cell mass, showing a promising path to commercially viable, intrinsically safe lithium batteries with high specific energy and high energy density.