Dual Regulation on Structure-Interface Enables Coal-Tar-Pitch-Based Hard Carbon Anodes with High Rate and Storage...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Coal-tar-pitch-based hard carbons (HCs) are promising anode materials for sodium-ion batteries (SIBs).
• Optimizing microstructure and surface chemistry is crucial for enhancing Na+ diffusion kinetics and sodium storage performance.
• Current challenges include controlling pore structure and surface states for superior battery performance.

Purpose of the Study:

• To develop a novel strategy for fabricating advanced hard carbon anodes for SIBs.
• To improve Na+ diffusion kinetics and sodium storage capacity through structural and chemical modifications.
• To investigate the impact of molecular crosslinking and CVD on carbon anode properties.

Main Methods:

• Utilized molecular crosslinking of polycyclic aromatic hydrocarbons (PAHs) in coal tar pitches (CTPs).
• Employed chemical vapor deposition (CVD) for surface carbon coating and pore structure modification.
• Applied post-heat treatment to regulate surface chemistry and optimize carbon anode performance.

Main Results:

• The optimized HPCV5-1200 anode demonstrated a high initial cycle efficiency (ICE) of 91.6%.
• Achieved a specific capacity of 320.2 mAh g-1 after 300 cycles at 0.2 A g-1.
• Exhibited excellent rate capability (112.6 mAh g-1 at 10 A g-1) and high energy density (233.5 Wh kg-1) in a full cell.

Conclusions:

• The proposed molecular crosslinking-coupled CVD strategy effectively optimizes hard carbon anodes for SIBs.
• Dual regulation of structure and interface significantly enhances sodium storage performance.
• The developed anodes offer a promising pathway for high-performance and high-energy-density sodium-ion batteries.