Quantum-Chemical Modeling of the Surface Contact of Superionic Conductor Li10GeP2S12 with Different Materials

Abstract

The bulk and surface of crystalline lithium-ion conductor Li₁₀GeP₂S₁₂ have been modeled by the density functional theory method in the generalized gradient approximation (GGA). It has been found that barriers to the migration of cations are small both along and across the unit cell, and that in this compound, ionic conductivity is possible in three dimensions. Modeling of the crystal surface has shown that it has a “bumpy” structure and poorly contacts with “hard” crystalline surfaces. With liquid electrolytes (for example, DMSO), such problems do not arise, and lithium cations can pass from one electrolyte to another without overcoming significant potential barriers. Upon contact with metallic lithium, Li₁₀GeP₂S₁₂ decomposes.