Architecting Sturdy Si/Graphite Composite with Lubricative Graphene Nanoplatelets for High-Density Electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Electrode densification via calendering is crucial for high-energy density lithium-ion batteries.
• Silicon anodes offer high energy density but are prone to cracking during calendering due to brittleness.

Purpose of the Study:

• To develop a strategy to prevent cracking and pulverization in silicon nanolayer-embedded graphite (Si/G) composites during electrode calendering.
• To enhance the mechanical robustness and electrochemical performance of Si/G anodes.

Main Methods:

• A mechanofusion process was used to coat Si/G composites with graphene nanoplatelets (GNP).
• The resulting GNP-coated Si/G (GNP-Si/G) composite was subjected to calendering and electrochemical testing.

Main Results:

• The GNP coating provided exceptional mechanical strength and lubricity, preventing Si nanolayer cracking and pulverization.
• GNP-Si/G composites exhibited superior cycling stability, with 15.6% higher capacity retention than P-Si/G after 300 cycles.
• The material achieved high electrode density (>1.6 g cm⁻³) and high areal capacity (>3.5 mAh cm⁻²) under industrial conditions.

Conclusions:

• Graphene nanoplatelets effectively mitigate the mechanical fragility of Si/G composites during electrode calendering.
• This approach offers a critical insight for the practical application of silicon anodes in high-energy lithium-ion batteries.