All-in-One Interface Engineering From Bulk to Electrode Toward High-Performance Micro-Sized Silicon Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon anodes offer high theoretical capacity but suffer from significant volume expansion (~300%) during cycling, leading to poor stability, especially for low-cost microsized silicon (µ-Si).
• Existing strategies often rely on organic binders and conductive additives, which can introduce complexity and compromise long-term performance.
• Effective interface engineering at both the particle and electrode levels is crucial for overcoming silicon anode limitations.

Purpose of the Study:

• To develop a novel electrode architecture for µ-Si anodes that addresses volume expansion and enhances electrochemical stability.
• To investigate the efficacy of an integrated co-carbonization (ICC) process for fabricating binder-free and additive-free silicon electrodes.
• To evaluate the electrochemical performance, including initial coulombic efficiency, cycling stability, and capacity retention, of the developed µ-Si@C/ICCE electrodes.

Main Methods:

• Fabrication of an integrated co-carbonized (ICC) electrode (µ-Si@C/ICCE) using µ-Si particles and a pre-binder, followed by a co-carbonization process.
• Characterization of the electrode structure to confirm uniform carbon layer distribution on µ-Si particles and at the electrode interface.
• Electrochemical testing, including galvanostatic cycling, to assess initial coulombic efficiency, long-term capacity retention, and areal capacity.

Main Results:

• The µ-Si@C/ICCE electrode was successfully fabricated without organic binders or conductive additives, featuring a uniform carbon layer on µ-Si particles and the electrode interface.
• The electrode demonstrated a high initial coulombic efficiency of 86.88% and robust mechanical stability.
• After 400 cycles, the µ-Si@C/ICCE electrode retained 1355 mAh g^-1 (84% retention), and a modified version (µ-Si@C+G/ICCE) achieved 6.13 mAh cm^-2 after 500 cycles (91% retention).
• A matched LiNi_0.8Co_0.1Mn_0.1O₂-based pouch cell confirmed the practical applicability of the µ-Si@C/ICCE electrode.

Conclusions:

• The integrated co-carbonization strategy effectively engineers both the silicon particle surface and the electrode interface, mitigating issues associated with silicon anode volume expansion.
• The binder-free and additive-free µ-Si@C/ICCE electrode exhibits excellent electrochemical performance and mechanical stability, offering a promising pathway for next-generation batteries.
• This approach provides a viable solution for enhancing the stability and commercial potential of silicon-based anodes in lithium-ion batteries.