Interlayer spacing enlarged 2D 1T-MoS₂ and V₂CT_x MXene as superior anodes for boosting potassium-ion diffusion...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Two-dimensional (2D) materials offer high theoretical capacitance for potassium ion batteries (PIBs).
• Challenges in PIBs include slow potassium ion diffusion and poor storage kinetics due to large ion size and narrow interlayer spacing.
• Developing advanced anode materials is crucial for high-performance PIBs.

Purpose of the Study:

• To design and synthesize a novel 2D composite anode material for enhanced potassium ion storage.
• To investigate the synergistic effects between 1T-MoS₂ and V₂CTₓ in improving ion diffusion and electrochemical performance.
• To evaluate the capacity, rate capability, and cycle stability of the developed anode in PIBs.

Main Methods:

• Magneto-hydrothermal synthesis of 1T-MoS₂@V₂CTₓ composite.
• Electrochemical characterization including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.
• Density Functional Theory (DFT) calculations to understand ion diffusion mechanisms and binding energies.

Main Results:

• The 1T-MoS₂@V₂CTₓ anode exhibited a high reversible capacity of 887.3 mA h g⁻¹ at 0.1 A g⁻¹.
• Excellent rate performance was achieved, retaining 563.6 mA h g⁻¹ at 2.0 A g⁻¹.
• Remarkable cycle stability was demonstrated, with capacity retention of 69.4% and 56.5% after 2000 cycles at 1.0 and 2.0 A g⁻¹, respectively.
• DFT calculations confirmed reduced ion diffusion energy barriers due to the synergistic effect.

Conclusions:

• The 1T-MoS₂@V₂CTₓ composite is a highly promising anode material for PIBs.
• The synergistic interaction between 1T-MoS₂ and V₂CTₓ significantly enhances potassium ion diffusion and storage.
• This work presents a new strategy for designing high-performance 2D composite electrodes for PIBs.