Highly stable few-layer V₂CT_x MXene/Carbon nanotube structure with restrained restacking for lithium ion storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• V2CTx MXene shows promise for lithium-ion batteries (LIBs) due to high theoretical capacity.
• Multilayer V2CTx structures suffer from nanosheet restacking, limiting cyclic stability.
• Developing strategies to prevent restacking is crucial for enhancing V2CTx performance in LIBs.

Purpose of the Study:

• To synthesize few-layer V2CTx/carbon nanotubes (CNTs) composite.
• To address the restacking problem of V2CTx nanosheets.
• To improve the electrochemical performance and stability of V2CTx-based electrodes for LIBs.

Main Methods:

• Synthesis of few-layer V2CTx/CNTs composite using tetramethylammonium hydroxide (TMAOH) delamination and electrostatic flocculation.
• Characterization of the composite structure and properties.
• Electrochemical testing of the composite as an electrode material for LIBs.

Main Results:

• Few-layer V2CTx nanosheets with a crimped structure were successfully synthesized, effectively inhibiting restacking.
• The incorporation of CNTs formed a conductive network and provided structural support, further preventing restacking.
• The V2CTx/CNT composite exhibited a high specific capacitance (621 mAh/g after 100 cycles at 0.1 A/g) and excellent rate capability (290 mAh/g at 5 A/g).
• The electrode demonstrated remarkable cycling stability, retaining 82.1% of its capacitance after 2000 cycles at 5 A/g.

Conclusions:

• The few-layer V2CTx/CNT composite effectively overcomes the restacking issue of V2CTx nanosheets.
• The composite exhibits superior electrochemical performance, including high capacity, rate capability, and cycling stability.
• This material holds significant potential for advanced lithium-ion battery applications.