Effect of H Defects on Li Transport during the Deposition Process on an H-Diamond Surface: A First-Principles Calculation Analysis

To explore the feasibility and rationality of a hydrogen-terminated diamond surface film as an solid electrolyte interface (SEI) for lithium-sulfur batteries, the adsorption and migration behavior of lithium atoms on the hydrogen-terminated diamond surface with different amounts of hydrogen defects are determined by first-principles calculations. Since a hydrogen deficiency in the row direction is denser than a hydrogen deficiency in the chain direction, hydrogen deficiency can drive lithium-ion deposition. Thus, lithium atoms are more stable on the surface of hydrogen-terminated diamonds with a hydrogen deficiency in the direction of the dimer row. The adsorption of lithium atoms on hydrogen-terminated diamond films lacking three hydrogens is more stable due to the absence of dangling chemical bonds on the surface of the hydrogen-terminated diamond. Therefore, lithium atoms cannot be adsorbed on an all-H-diamond surface. The low adsorption energy of lithium atoms on a clean diamond surface indicates that it is a simple physical adsorption. H termination increases the adsorption energy and migration activation energy of Li on the diamond surface. H termination changes the migration path of Li on the diamond surface. The atomic deposition of Li is driven by the center of the H defect region on the H-diamond surface.