Gregory T. Hitz, Dennis W. McOwen, Lei Zhang, Zhaohui Ma, Zhezhen Fu, Yang Wen, Yunhui Gong, Jiaqi Dai, Tanner R. Hamann, Liangbing Hu, Eric D. Wachsman

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 Li7La3Zr2O12 (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-cm2) dramatically lower, and current densities dramatically higher (10?mA/cm2), 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.