Induced orbital asymmetry of nonpolar molecular additives for boosted rapid operating performance in lithium metal batteries

Abstract

Lithium metal batteries (LMBs) have emerged as a promising next-generation energy storage solution owing to their high energy density; however, the uncontrolled growth and short circuits of lithium dendrites on lithium metal anodes result in short lifespans and severe safety concerns. In this study, we introduced highly polarizable and nonpolar molecular additives into the electrolyte to stabilize the lithium metal anode surface, emphasizing the role of the induced dipole effects in these molecules. Specifically, we compared the effects of benzene and anthracene additives, both nonpolar molecules with different polarizabilities, on the performance of LMBs. Our findings reveal that larger and more polarizable anthracene molecules flatten the lithium metal surface and significantly enhance the cycling stability under high current densities, even up to 10 mA cm⁻². The crystalline orientation of lithium metal was controlled along the planar (110) direction, and a durable solid electrolyte interface layer was formed owing to the active surface coordination of the highly polarizable anthracene. This study underscores the pivotal influence of molecular polarizability in guiding the design of electrolyte additives. It paves the way for developing long-lasting and high-performance LMBs.