Durable Interphase Engineering on SiO_x Anodes Through Interfacial-Enrichment-Facilitated Polymerization

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Solid electrolyte interphase (SEI) construction is crucial for silicon-based anode performance.
• Existing SEI strategies face challenges in achieving both uniformity and long-term stability.

Purpose of the Study:

• To develop a synergistic strategy for SEI formation integrating interfacial modification and in situ electrolyte decomposition.
• To enhance the performance and stability of silicon oxide (SiOₓ) anodes.

Main Methods:

• Pre-formation of a conformal LiF and Li₃PO₄ layer on SiOₓ anodes.
• Utilizing Li₃PO₄ for selective adsorption of fluoroethylene carbonate (FEC) to promote polymerization.
• In situ regulation of electrolyte decomposition for SEI repair.

Main Results:

• The synergistic SEI provides a stable mechanical framework (LiF) and promotes the formation of high-molecular-weight organic species (from FEC polymerization).
• The dynamic repair mechanism compensates for volume expansion damage, ensuring SEI integrity and resilience.
• Modified SiOₓ anodes demonstrated excellent cycling stability (81% retention over 300 cycles) and high-rate capability (1010 mAh g⁻¹ at 2.4 A g⁻¹).

Conclusions:

• The integrated SEI design offers a robust solution for stabilizing silicon-based anodes.
• This work presents a new paradigm for dynamic repair interphases in high-capacity anodes.
• The findings pave the way for improved battery energy density and lifespan.