Electrochemical and Defect Characterization of APTES-Functionalized Ti₃C₂T_x MXene for Supercapacitor Devices

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• MXenes are promising 2D materials for energy storage applications.
• Functionalization is key to optimizing MXene properties.
• Existing methods often require conductive additives.

Purpose of the Study:

• To investigate APTES functionalization of MXene for high-performance electrodes.
• To evaluate electrochemical properties without conductive polymers, metal oxides, or carbon.
• To assess the impact of APTES on ion accessibility and charge storage mechanisms.

Main Methods:

• Synthesis and characterization of MAX phase, MXene, and APTES-MXene.
• Electrochemical testing using a two-electrode system.
• Electrochemical impedance spectroscopy (EIS) and Dunn analysis for charge storage mechanism determination.

Main Results:

• APTES-MXene electrode achieved a specific capacitance of 207.62 F g⁻¹, energy density of 28.83 Wh kg⁻¹, and 93.8% capacity retention.
• Surface-controlled charge storage was dominant, with a capacitive contribution of 70.61%.
• APTES modification increased charge transfer resistance, indicating altered ion transport and extended interlayer distance.

Conclusions:

• APTES functionalization offers a pathway to high-performance MXene electrodes for energy storage.
• The functionalized MXene demonstrates excellent capacity and cycle stability.
• Two-electrode measurements are crucial for evaluating realistic material performance.