Lithium Pre‐Storage Enables High Initial Coulombic Efficiency and Stable Lithium‐Enriched Silicon/Graphite Anode

Abstract

Application of silicon‐based anode is significantly challenged by low initial Coulombic efficiency (ICE) and poor cyclability. Traditional pre‐lithiation reagents often pose safety concerns due to their unstable chemical nature. Achieving a balance between water‐stability and high ICE in prelithiated silicon is a critical issue. Here, we present a lithium‐enriched silicon/graphite material with an ultra‐high ICE of ≥110% through a high‐stable lithium pre‐storage methodology. Lithium pre‐storage prepared a nano‐drilled graphite material with surficial lithium functional groups, which can form chemical bonds with adjacent silicon during high‐temperature sintering. This results in an unexpected O‐Li‐Si interaction, leading to in‐situ pre‐lithiation of silicon nanoparticles and providing high stability characteristics in air and water. Additionally, the lithium‐enriched silicon/graphite materials impart a combination of high ICE, high specific capacity (620 mAh g‐1), and long cycling stability (> 400 cycles). This study opens up a promising avenue for highly air and water‐stable silicon anode prelithiation methods.