Refining Chemical Evolution of Resin Toward High-Performance Hard-Carbon Anodes.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hard carbon (HC) anodes are crucial for sodium-ion batteries but face limitations due to slow ion insertion kinetics in closed pores.
• Current methods to improve HC performance often involve templates or additives, which can reduce structural precision or scalability.

Purpose of the Study:

• To develop a molecular engineering strategy for enhancing HC anode performance in sodium-ion batteries.
• To create a scalable and template-free synthesis pathway for high-performance HC materials.

Main Methods:

• Tailoring the pre-condensation of resorcinol-formaldehyde resin to control volatile evolution and polycyclic aromatic hydrocarbon alignment during pyrolysis.
• Synthesizing HC architectures with increased accessible closed pores and expanded pseudo-graphitic domains.

Main Results:

• The optimized HC anode exhibited an enhanced low-voltage plateau capacity (255.5 mAh g⁻¹), a total reversible capacity of 349.8 mAh g⁻¹ at 60 mA g⁻¹, and an initial Coulombic efficiency (ICE) of 86.69%.
• The anode maintained a capacity of 260.8 mAh g⁻¹ at a high rate of 200 mA g⁻¹.
• The strategy's versatility was confirmed with a resorcinol-amine resin, yielding a capacity of 360.8 mAh g⁻¹ and an ICE of 83.17%.

Conclusions:

• Molecular precursor regulation provides a scalable, template-free route to high-performance hard carbon anodes.
• This approach significantly improves ion-insertion kinetics and overall battery performance for sodium-ion applications.