Reactant conversion-intercalation strategy toward interlayer-expanded MoS₂ microflowers with superior supercapacitor...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Conventional synthesis of layered materials like molybdenum disulfide (MoS₂) often involves complex procedures and external templates.
• There is a need for simplified strategies to engineer the interlayer spacing of MoS₂ for enhanced electrochemical applications.

Purpose of the Study:

• To develop a facile reactant conversion-intercalation strategy for synthesizing interlayer-expanded MoS₂ (E-MoS₂).
• To investigate the supercapacitor performance of the synthesized E-MoS₂.
• To understand the mechanism behind the enhanced electrochemical properties through theoretical calculations.

Main Methods:

• Employed a reactant conversion-intercalation strategy using thiourea as both reactant and intercalator precursor.
• Synthesized E-MoS₂ by converting thiourea to ammonium thiocyanate for in situ intercalation.
• Evaluated supercapacitor performance using three-electrode and symmetric supercapacitor systems.
• Conducted density functional theory (DFT) calculations to analyze structural and electronic properties.

Main Results:

• Synthesized E-MoS₂ with an expanded interlayer spacing of 9.4 Å.
• E-MoS₂ electrodes exhibited a specific capacity of 246.8 F g^-1 at 0.5 A g^-1, significantly outperforming pristine MoS₂ (42.5 F g^-1).
• A symmetric supercapacitor using E-MoS₂ achieved a high specific capacity of 261.3 F g^-1, energy density of 13.3 W h kg^-1, and 81.7% capacity retention after 3000 cycles.
• DFT calculations confirmed effective NH₄⁺ and SCN^- intercalation, leading to enhanced Na⁺ adsorption and low diffusion barriers.

Conclusions:

• The developed reactant conversion-intercalation strategy provides a simple and effective route to synthesize E-MoS₂.
• E-MoS₂ demonstrates superior electrochemical performance for supercapacitor applications due to expanded interlayer spacing and favorable ion adsorption/diffusion.
• This strategy offers a promising approach for interface engineering of layered materials for advanced energy storage.