Hierarchical Sulfide-Rich Modification Layer on SiO/C Anode for Low-Temperature Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon oxide/graphite (SiO/C) composite anodes are promising for next-generation Li-ion batteries, offering high energy density (>400 Wh kg⁻¹).
• Practical application is hindered by rapid capacity decay and safety concerns, especially at low temperatures.

Purpose of the Study:

• To fabricate a sulfide-rich solid electrolyte interface (SEI) layer on SiO/C anodes.
• To improve the reversible lithium storage performance of SiO/C anodes at low temperatures.

Main Methods:

• Fabrication of a multi-layered, inorganic-organic hybrid SEI on SiO/C anode surfaces.
• Characterization using time-of-flight secondary ion mass spectrometry (TOF-SIMS).
• Electrochemical testing of the modified anode coupled with a LiNi₀.₈Co₀.₁Mn₀.₁O₂ cathode at -20 °C.
• First-principles calculations to understand ion transport mechanisms.

Main Results:

• The SEI layer consists of three continuous layers with uniform distribution of ROSO₂Li, ROCO₂Li, and LiF.
• The modified anode achieved 73% capacity retention at -20 °C.
• First-principles calculations confirmed enhanced Li⁺ desolvation and inhibited dendrite growth due to the SEI structure.

Conclusions:

• The developed sulfide-rich SEI layer effectively boosts low-temperature performance of SiO/C anodes.
• The unique layered structure of the SEI facilitates ion transport and improves stability.
• This approach offers a new strategy for advancing SiO/C anodes and low-temperature Li-ion batteries.