High-Compaction Spherical Carbon with Tunable Rich Pore Structures for Efficient Sodium Storage.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hard carbon is a promising anode for sodium-ion batteries (SIBs) due to its tunable pore structure.
• A major challenge for SIBs is balancing pore volume for sodium storage with high compaction density.

Purpose of the Study:

• To develop a pre-pore engineering strategy for high-compaction-density spherical hard carbon anodes.
• To simultaneously enhance gravimetric and volumetric capacities in SIBs.

Main Methods:

• Fabrication of spherical hard carbon with tunable pore structures using a pre-pore engineering strategy.
• Investigation of the effects of pore structure regulation on electrochemical performance at microscopic, mesoscopic, and macroscopic scales.

Main Results:

• Optimized hard carbon exhibited a reversible capacity of 375.40 mAh g⁻¹ and initial Coulombic efficiency of 90.1%.
• High-compaction anodes achieved a reversible capacity of 359.49 mAh g⁻¹ and volumetric capacity of 390.30 mAh cm⁻³.
• An Ah-level pouch cell demonstrated practical potential.

Conclusions:

• Pore structure engineering is crucial for optimizing hard carbon anodes for SIBs.
• The developed strategy effectively enhances both gravimetric and volumetric energy densities.
• Fabrication methods significantly influence electrode structure and sodium storage behavior.