MXene-Induced Pseudocapacitive Transformation in Battery-Type Metal Sulfide: A Paradigm for High-Rate Sodium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Sluggish kinetics in battery-type materials limit high-rate sodium-ion storage.
• Developing advanced electrode materials is crucial for next-generation energy storage solutions.

Purpose of the Study:

• To present a universal MXene-enabled capacitive enhancement strategy for high-rate sodium-ion storage.
• To transform battery-type materials into pseudocapacitive electrodes through interfacial modulation.

Main Methods:

• Fabrication of a porous 0D/2D heterostructure using interlayer-confined SnS2 quantum dots (QDs) within Ti3C2Tx MXene.
• Utilizing quantum confinement and interfacial electronic coupling to modify Na+ storage mechanisms.
• Characterization of electrochemical performance, including capacity, cycling stability, and ion diffusion coefficients.

Main Results:

• The MXene/SnS2 QD heterostructure demonstrated a significant shift towards pseudocapacitive behavior (94% contribution at 2 mV s-1).
• The electrode delivered a high capacity of 348 mAh g-1 at 0.05 A g-1 with excellent cycling stability (88.8% retention after 3000 cycles).
• Achieved fast Na+ diffusion coefficients in the range of 10-10 to 10-11 cm2 s-1.

Conclusions:

• Interfacial modulation via MXene nanoconfinement is a powerful strategy to enhance pseudocapacitive energy storage.
• The developed material offers a promising pathway toward high-rate and durable sodium-ion energy storage devices.
• This work provides a general design principle for optimizing battery-type materials for capacitive energy storage.