Nature of Sigma-Type Lithium Bonding Interaction in Nanoscale

Abstract

Li-based rechargeable batteries are becoming popular power sources for biomedical devices and healthcare equipment. In nanoscale, lithium bonds may associate with intermolecular noncovalent interactions when Li atoms are shared by adjacent atoms inside rechargeable Li batteries. Theoretical study of lithium boding interactions thus is of paramount importance for a better understanding of the working mechanisms and designing high-efficient electrode–electrolyte interfaces from nanolevel for Li-based batteries. In this study, we used state-of-the-art theoretical methods, with inclusion of density functional theory/symmetry-adapted perturbation theory (DFT/SAPT), density functional reactivity theory (DFRT) and energy decomposition analysis (EDA), to delve into the nature of lithium bonding interactions. Our results showed that B3LYP outperforms all other functionals under consideration in the conventional supramolecular scheme, indicating that the formation of a lithium bond is not dispersion-driven. The calculated PBE0/SAPT and B3LYP/EDA data are consistent with each other, unravelling that the lithium bond is mainly of an electrostatically driven nature. Both steric hindrance and exchange-correlation potentials also make important contributions when two-variable fitting is considered. These results provide new sight in understanding lithium atom interactions for potential lithium-based batteries applications.