Recent Progress in MXene-Based Supercapacitors: From Synthesis and Surface Engineering to Next-Generation...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• MXenes are 2D layered transition metal carbides, nitrides, and carbonitrides with unique properties for energy storage.
• Their metallic conductivity, hydrophilic surfaces, and tunable chemistry enable efficient charge storage via pseudocapacitance and ion intercalation.
• MXenes offer advantages over traditional carbon and metal-oxide electrode materials in supercapacitors.

Purpose of the Study:

• To review the synthesis methods, structural engineering strategies, and charge storage mechanisms of MXene-based supercapacitors.
• To highlight the electrochemical performance and potential applications of MXenes in energy storage.
• To discuss the challenges and future development of MXenes for advanced energy storage systems.

Main Methods:

• Selective etching (HF, alkali, electrochemical, molten salts, non-etching) and CVD techniques for MXene synthesis.
• Structural engineering via surface functionalization and integration with other materials (graphene, CNTs, polymers).
• Electrochemical characterization to evaluate specific capacitance, energy density, power density, and cycling stability.

Main Results:

• MXene electrodes achieved specific capacitances >1500 F/g, energy densities ~80 Wh/kg, and power densities >10 kW/kg.
• Capacitance retention exceeded 90% after 10,000 cycles, demonstrating excellent stability.
• Charge storage involves a combination of electric double-layer capacitance and pseudocapacitive reactions.

Conclusions:

• MXenes show significant potential as advanced electrode materials for high-performance supercapacitors.
• Structural engineering effectively mitigates challenges like oxidation and restacking, improving ion accessibility.
• MXenes are a promising platform for next-generation energy storage systems and wearable electronics.