Multifunctional carbon layers design enabling high-performance micro-sized silicon anodes for advanced lithium-ion...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Graphite/micro-sized silicon (Gr/μm-Si) anodes offer high capacity for next-generation lithium-ion batteries.
• Challenges include excessive solid electrolyte interphase (SEI) formation and electrical disconnection due to silicon volume expansion.

Purpose of the Study:

• To optimize Gr/μm-Si anode material using a multifunctional carbon layer (MCL).
• To mitigate side reactions, ensure stable SEI formation, and enhance structural integrity and conductivity.

Main Methods:

• Preparation of a multifunctional carbon layer (MCL) using in situ grown carbon nanotubes (CNTs) and pyrolytic carbon from polyacrylonitrile.
• Integration of MCL with Gr/μm-Si to form Gr/Si@MCL anodes.
• Electrochemical performance testing, including capacity retention and full-cell evaluation with LiFePO₄.

Main Results:

• The Gr/Si@MCL anode achieved a discharge specific capacity of 503.6 mAh g⁻¹.
• Exceptional capacity decay of only 0.031% per cycle after 500 cycles at 1 A g⁻¹.
• A full-cell (Gr/Si@MCL||LiFePO₄) demonstrated a high energy density of 347 Wh kg⁻¹.

Conclusions:

• The MCL effectively anchors CNTs, isolates Si, and buffers volume expansion, leading to stable SEI formation.
• The robust 3D conductive network enhances electron/ion transport and mechanical stability.
• The developed Gr/Si@MCL anode shows significant potential for practical application in advanced energy storage devices.