Pore modulation in coal-based hard carbon for sodium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Developing high-performance sodium-ion batteries requires improved low-voltage sodium storage capacity in hard carbon anodes.
• The closed-pore structure of hard carbon is crucial for enhancing sodium storage but is challenging to design.
• Optimizing hard carbon's pore architecture is key to unlocking its full potential in energy storage applications.

Purpose of the Study:

• To design and optimize the closed-pore structure of hard carbon for enhanced low-voltage sodium storage.
• To investigate the relationship between briquetting pressure, pore structure, and sodium storage performance.
• To provide insights into improving coal-based hard carbon anodes for sodium-ion batteries.

Main Methods:

• Utilized a briquetting process combined with a templating method to modulate hard carbon's pore architecture.
• Adjusted briquette pressure to control magnesium ion etching and precursor cross-linking.
• Analyzed the effect of pore structure modification on sodium storage capacity at low potentials.

Main Results:

• The briquetting process effectively modulated the closed-pore content of hard carbon.
• The HC-3 anode, prepared at 3 MPa, demonstrated a high reversible capacity of 366 mA h g⁻¹ at 20 mA g⁻¹.
• A significant capacity of 224 mA h g⁻¹ was achieved below 0.1 V, indicating excellent low-voltage performance.

Conclusions:

• The study successfully optimized hard carbon's pore structure for superior sodium storage.
• Controlling briquette pressure is an effective strategy to enhance closed-pore content and low-voltage performance.
• This research offers valuable insights for developing advanced hard carbon anodes for sodium-ion batteries.