Regulating the Nanosheets Structures in Pitch-Derived Amorphous Carbons for Efficient Sodium-Ion Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Amorphous carbon (AC) is a cost-effective anode material for sodium-ion batteries (SIBs).
• AC's amorphous structure presents challenges in balancing high capacity and rate capability.
• Developing advanced anode materials is crucial for high-performance SIBs.

Purpose of the Study:

• To engineer the nanosheet structure of pitch-derived amorphous carbon (PDAC) for improved SIB performance.
• To investigate the relationship between nanosheet structure, pore volume, and sodium storage mechanisms.
• To achieve simultaneous enhancement of rate capability and high capacity in PDAC anodes.

Main Methods:

• Controlled growth of polycyclic aromatic hydrocarbons during pre-polymerization to regulate PDAC nanosheet structure.
• Characterization of nanosheet length, interlayer spacing, and closed pore volume.
• Electrochemical testing of PDAC anodes in ester-based electrolytes for SIBs.

Main Results:

• PDAC nanosheets were regulated to 12.27 nm, increasing closed pore volume to 0.062 cm³ g⁻¹.
• Specific capacity reached 377.4 mAh g⁻¹ with a significant plateau contribution (68.0%).
• High rate performance demonstrated: 357.8 mAh g⁻¹ at 200 mA g⁻¹ and 253.6 mAh g⁻¹ at 500 mA g⁻¹.
• Exceptional cycling stability achieved, retaining 90.4% capacity after 1000 cycles.

Conclusions:

• Regulating PDAC nanosheet length and interlayer spacing enhances Na⁺ storage efficiency.
• Increased closed pore volume facilitates quasi-metallic sodium cluster formation, boosting capacity.
• The developed PDAC material shows great promise for fast-charging, high-capacity SIBs.