Elastic MXene conductive layers and electrolyte engineering enable robust potassium storage.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Material structure critically dictates properties, especially for ion storage.
• Designing stable structures is key for efficient alkali metal ion battery cycling.

Purpose of the Study:

• To engineer a novel MXene-based anode for potassium-ion batteries (PIBs).
• To enhance structural integrity and electrochemical performance through material design and electrolyte optimization.

Main Methods:

• Fabrication of Ti3C2Tx-Co@NCNTs with self-grown carbon nanotubes for structural support.
• Optimization of electrolyte and solid electrolyte interphase (SEI) layer composition.
• Electrochemical performance testing (cycling stability, capacity).
• Mechanistic studies and density functional theory (DFT) calculations.

Main Results:

• Ti3C2Tx-Co@NCNTs demonstrated a reversible capacity of 260 mA h g-1 after 2000 cycles at 500 mA g-1.
• A robust inorganic SEI layer enriched with KF was formed, inhibiting side reactions.
• DFT calculations confirmed superior electronic conductivity and lower K+ diffusion barriers.

Conclusions:

• The developed Ti3C2Tx-Co@NCNTs anode significantly improves cycling stability and capacity in PIBs.
• Optimized electrolyte and SEI layer are crucial for high-performance MXene-based anodes.
• This work provides a framework for designing advanced MXene anodes for PIBs.