Screening of Lithium Ionic Conductors in Reference to the Formation of Interface with Lithium Anode

Solid-state batteries with lithium as the anode and ceramic oxides, sulfides, or phosphate as the solid electrolyte are considered presently for their high energy density and nonflammable nature of the electrolyte. This presentation demonstrates the use of open-source databases to identify suitable lithium-bearing compounds that can serve as electrolyte. The primary screening was based on the electrical conductivity, structural stability, and avoidance of chemical decomposition at the cathode. Subsequent screening considered the probability of the compound to be a superionic conductor based on several related descriptors, extracted from the crystal information file. The electrochemical stability of the compound at the interface with the lithium anode was evaluated from the Grand potential phase diagram. The applied voltage was varied such that the chemical potential of lithium changes and in turn influences the Grand potential phase diagram, leading to interface products when the voltage is outside the electrochemical stability window. The range of voltage within which a screened electrolyte is stable at the interface was derived accordingly. The interface products, wherever applicable, were further reviewed with reference to their electrical and ionic conductivities to ascertain the stability of the interface. The formation of interface products, as predicted by the Grand potential phase diagram from the database, was reviewed vis-à-vis the same reported in the literature from the first-principle analysis.