HCl-Based Hydrothermal Etching Strategy toward Fluoride-Free MXenes.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• MXenes, with their unique 2D structure, show promise for energy storage applications.
• Conventional MXene synthesis uses hazardous fluoride reagents, leading to surface defects that hinder performance.
• Inert fluoride functional groups negatively impact the electrochemical properties of MXenes.

Purpose of the Study:

• To investigate the feasibility of using hydrochloric acid (HCl) for fluoride-free MXene synthesis.
• To experimentally demonstrate the production of fluoride-free Molybdenum Carbide (Mo2C) MXenes.
• To evaluate the electrochemical performance of HCl-etched Mo2C MXenes in energy storage devices.

Main Methods:

• Density Functional Theory (DFT) calculations to assess HCl etching feasibility on MAX phases.
• Experimental synthesis of Mo2C MXenes using HCl as a fluoride-free etchant.
• Electrochemical testing of synthesized Mo2C MXenes in supercapacitors and sodium-ion batteries.

Main Results:

• DFT calculations confirmed the etching feasibility of HCl on various MAX phases.
• Fluoride-free Mo2C MXenes were successfully synthesized with high efficiency (approx. 98%).
• The resulting Mo2C electrodes demonstrated superior electrochemical performance in supercapacitors and sodium-ion batteries.

Conclusions:

• Hydrochloric acid (HCl) offers a viable route for synthesizing fluoride-free MXenes.
• This novel synthesis strategy significantly improves the electrochemical performance of Mo2C MXenes.
• The development of fluoride-free MXenes opens new avenues for advanced energy storage solutions.