Li-Si alloy pre-lithiated silicon suboxide anode constructing a stable multiphase lithium silicate layer promoting...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon suboxide (SiOₓ) anodes are promising for high-capacity batteries but suffer from poor initial Coulombic efficiency (ICE) and cycling stability.
• Improving ICE and stability is critical for the commercialization of SiOₓ anodes.
• Existing methods often compromise reversible capacity or add complexity.

Purpose of the Study:

• To develop an economical and effective method for enhancing the ICE and cycling stability of SiOₓ anodes.
• To create pre-lithiated core-shell SiOₓ anodes with a robust, functional surface layer.
• To investigate the role of the pre-lithiated layer in improving electrochemical performance.

Main Methods:

• Pre-lithiation of SiOₓ using lithium silicon alloy (Li₁₃Si₄) to form a core-shell structure.
• Formation of a nanoscale multiphase lithium silicate (Li₂SiO₃, Li₄SiO₄, Li₂Si₂O₅) surface layer.
• Electrochemical characterization, including ICE and cycling stability measurements.
• Analysis using dynamic electrochemical impedance spectroscopy (dEIS) and distribution of relaxation time (DRT).

Main Results:

• The pre-lithiated SiOₓ anode achieved a high ICE of 85.3% and a specific capacity of 1771.5 mAh g⁻¹.
• The multiphase lithium silicate layer provided mechanical robustness, acting as a buffer against volume expansion.
• The layer enhanced Li-ion diffusion kinetics and promoted the formation of a stable solid electrolyte interphase (SEI).

Conclusions:

• The proposed pre-lithiation strategy effectively enhances the ICE and cycling stability of SiOₓ anodes.
• The nanoscale multiphase lithium silicate layer is key to improving interfacial stability and electrochemical performance.
• This approach offers a practical and scalable method for developing high-performance SiOₓ anodes for energy storage applications.