Preparation of Nano- and Microstructured Garnet Li7La3Zr2O12 Solid Electrolytes for Li-Ion Batteries via Cellulose Templating

Lithium lanthanum zirconate (LLZO) is a promising Li+ ion conductor for applications as a ceramic solid electrolyte in all-solid-state lithium batteries. However, the tetragonal and cubic phases of LLZO differ in lithium ionic conductivity by several orders of magnitude with extrinsic dopants or nanostructuring often required to stabilize the high conductivity cubic phase at room temperature. Here, we show that nanostructured LLZO can be prepared by templating onto various cellulosic fibers, including laboratory Kimwipes, Whatman filter paper, and nanocellulose fibrils, followed by calcination at 700–800 °C. The effect of templating material, calcination temperature, calcination time, and heating ramp rate on the LLZO crystal structure and morphology were thoroughly investigated. Templating was determined to be an effective method for controlling the LLZO size and morphology, and low calcination times and ramp rates were found to favor the formation of small ligaments. Furthermore, it was verified that cu...