First-principles study on a lithium fluorooxoborate solid ion conductor

Abstract

Solid-state lithium-ion batteries have garnered significant interest due to their enhanced safety and superior energy density. A key component within solid-state batteries is the solid electrolyte, which plays a vital role in the battery's performance. In this work, we delve into the electronic structures and ionic diffusion characteristics of lithium fluorooxoborate, Li₂B₃O₄F₃ (LBOF), as a potential solid electrolyte material by First-principles calculations. The calculations indicate that the limited connectivity of low-energy barrier (0.08 eV) ion migration pathways, combined with significant vacancy formation energy (∼6.0 eV), results in the poor ionic conductivity in crystalline LBOF. Additionally, we explore an effective strategy to reduce the hopping distance for lithium ions by inducing local disorder in LBOF, thereby enhancing its ionic conductivity properties. Our insights have shed new light on the strategies to alter ionic conductivity in the field of solid electrolyte materials, thus accelerating the innovation of solid-state battery technology.