Lithium has important applications, not only in modern battery technology but also, e.g., in organolithium reagents for organic syntheses. Commercially available lithium powders or dispersions can be used for the preparation of such organolithium reagents. However, their supply can be limited, and their preparation can require harsh conditions that are not practical for an academic laboratory. The physical form influences the reactivity of metallic lithium. Thus, alternative reactive forms of Li that can be easily prepared and used in the lab would be useful.
Andy A. Thomas, Texas A&M University, College Station, USA, and colleagues have developed a method for the preparation of highly reactive lithium metal dendrites via a simple and convenient activation using liquid ammonia. The team dissolved lithium in liquid ammonia at –78 °C. The resulting solution was stirred and warmed to room temperature, and the ammonia was slowly removed by evaporation.
Under these conditions, lithium dendrites grow on the walls of the reaction vessels. The dendrites can be used directly in further reactions or recovered and stored under an inert atmosphere. The team found that the dendrites show clean surfaces and have specific surface areas that are about 100 times higher than those of available Li powders (115,000 cm2/g vs. 1,100 cm2/g, respectively). Due to these properties, the dendrites also reached higher reaction rates. This freshly activated lithium can be used for the reproducible synthesis of organolithium reagents in the lab.
- Preparation of Highly Reactive Lithium Metal Dendrites for the Synthesis of Organolithium Reagents,
Michael P. Crockett, Lupita S. Aguirre, Leonel B. Jimenez, Han-Hsiang Hsu, Andy A. Thomas,
J. Am. Chem. Soc. 2022.