Fluorine-Free MXenes: Recent Advances, Synthesis Strategies, and Mechanisms

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• MXenes are 2D materials with excellent conductivity, mechanical strength, and tunable bandgaps.
• Conventional synthesis uses fluorine-based etchants, causing environmental issues and defects.
• Need for sustainable and effective MXene synthesis methods is critical.

Purpose of the Study:

• To review environmentally friendly, fluorine-free MXene synthesis techniques.
• To highlight mechanisms, recent advancements, and alternative etching strategies.
• To discuss the impact of fluorine-free terminations on MXene properties and applications.

Main Methods:

• Electrochemical etching
• Lewis acid-driven molten salt etching
• Alkaline/hydrothermal techniques
• Chemical Vapor Deposition (CVD)
• Novel innovative methods

Main Results:

• Fluorine-free synthesis yields terminations like -O, -OH, and -Cl, enhancing surface chemistry.
• -OH terminations improve energy storage; -Cl terminations optimize electrochemical performance.
• Mitigation of fluorine's adverse effects on conductivity leads to improved electronic properties.

Conclusions:

• Fluorine-free MXene synthesis presents a sustainable pathway with enhanced material properties.
• These methods offer broader applications by improving conductivity and surface functionality.
• Further research into challenges, opportunities, and future perspectives is warranted.