Sonochemically Prepared Nanodot Magnesium Fluoride-Based Anodeless Carbon Substrate for Simultaneously Reinforcing Interphasial and Reaction Kinetics for Sulfide-Based All-Solid-State Batteries

Abstract

“Anodeless” electrodes for all-solid-state batteries (ASSBs) have been attracting attention as a solution for achieving high energy density. Recent studies on anodeless electrodes have shown improvements in cycle life and energy density through the stabilization of plated lithium (Li) using Li-soluble metals (e.g., Ag, Zn, etc.). In this study, magnesium-based materials (MgF₂@C) are introduced for use as an anodeless electrode. Nanodot magnesium fluoride (MgF₂) is synthesized onto a carbon black surface via sonochemical synthesis. MgF₂ is converted to a Mg-Li alloy and LiF during lithiation. The Mg-Li alloy from the MgF₂@C anodeless electrode reduces lithiation overpotential and provides a uniform and dense Li layer between the current collector and the anodeless electrode. The ASSB cell assembled with the MgF₂@C anodeless electrode exhibits 81.4% capacity retention after 200 cycles at 30 °C.