Stainless Steel-Like Passivation Inspires Persistent Silicon Anodes for Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Passivation is crucial for material stability, commonly seen in stainless steel with Cr2O3 layers.
• Silicon anodes offer high theoretical capacity for lithium-ion batteries but suffer from poor cycling stability due to volume changes.

Purpose of the Study:

• To adapt the passivation concept for silicon anodes in lithium-ion batteries.
• To investigate the mechanism of LiF/Li2CO3 passivation in bulk silicon.
• To enhance the electrochemical performance and durability of silicon anodes.

Main Methods:

• Incorporation of LiF/Li2CO3 passivators into bulk silicon.
• Ex situ characterizations and redox peak contour mapping.
• Thickness evolution tests and finite element simulations.

Main Results:

• Passivation enhances Li-Si alloy (de)lithiation and induces a F-rich solid electrolyte interphase.
• The Si/LiF/Li2CO3 composite demonstrates improved stability and mitigated volume changes.
• The 3D passivated Si anode retains 3701 mAh/g after 1500 cycles and tolerates high rates up to 50C.

Conclusions:

• The LiF/Li2CO3 passivation strategy effectively improves silicon anode performance and longevity.
• This approach offers a pathway for constructing robust silicon anodes for advanced lithium-ion batteries.
• The findings provide valuable insights into material design for next-generation energy storage solutions.