Rigid organic molecule pillared Ti₃C₂ towards high rate capability and fast sodium ion storage

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Two-dimensional MXenes are promising anode materials for rechargeable batteries.
• Challenges include self-stacking and sluggish sodium diffusion, limiting performance.
• Existing MXene anodes suffer from poor rate capability and cycling stability.

Purpose of the Study:

• To enhance the performance of MXene (Ti3C2) anodes for sodium-ion batteries.
• To overcome the limitations of self-stacking and slow sodium diffusion kinetics.
• To develop a novel interlayer engineering strategy for improved energy storage.

Main Methods:

• Utilized an organic molecular pillaring strategy using 3,3',4,4'-benzene tetracarboxylic acid (BTCA).
• Chemically pillared BTCA molecules into Ti3C2 interlayers via dehydration condensation reaction.
• Characterized the modified Ti3C2-BTCA material for structural and electrochemical properties.

Main Results:

• Expanded interlayer spacing of Ti3C2 using rigid BTCA pillars.
• Achieved a reversible capacity of 182.3 mA h g⁻¹ at 0.1 A g⁻¹ after 2000 cycles with 77.9% retention.
• Demonstrated a significantly enhanced sodium diffusion coefficient (6.6 × 10⁻⁷ cm² s⁻¹) compared to pristine Ti3C2.

Conclusions:

• The organic molecular pillaring strategy effectively enhances MXene anode performance.
• Ti3C2-BTCA exhibits superior rate capability and cycling stability for sodium-ion storage.
• This approach provides a viable route for developing high-performance Na+ storage materials.