In-situ formed LiAlO2 coating enabling the prelithiated SiOx@C anode with enhanced initial coulombic efficiency and electrochemistry-active solid-state interfaces

Abstract

The prelithiated SiO_x anode showcases markedly improved Li-storage capabilities compared to its unlithiated counterparts, yet it faces hurdles such as slurry gassing, electrolyte deterioration, and capacity fade attributed to residual alkali and an unstable electrolyte/anode interface. To tackle these challenges, we propose a strategic utilization of residual alkali by creating an in-situ γ-LiAlO₂ functional layer on the prelithiated SiO_x@C anode material. This is accomplished by incorporating a minor amount of Al₂O₃ into the SiO_x@C/LiH precursor mixture before the solid-phase prelithiation process. The resulting modified prelithiated SiO_x@C anode with in-situ formed electrolyte-isolating γ-LiAlO₂ layer exhibits no discernible slurry gas generation within 7 days and substantially mitigates side reactions with the electrolyte, thereby boosting the initial coulombic efficiency and cycling stability of the SiO_x@C anode. In half-cell evaluations, the prelithiated SiO_x@C anode demonstrates a high Li-storage capacity of 1323 mAh g⁻¹ and an impressive initial coulombic efficiency of 91.09%. When assessed in a 3.2 Ah 18,650 cylindrical battery, the prelithiated SiO_x@C anode showcases exceptional cyclability, retaining 81% of its capacity after 1000 cycles, underscoring its potential for practical applications. This study introduces a scalable and cost-effective prelithiation technique that propels the development and practical deployment of Si-based anodes by resolving persistent scientific challenges with the use of inexpensive additives.