3D self-assembled VS₄ microspheres with high pseudocapacitance as highly efficient anodes for Na-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Surface structure is critical for battery capacity and kinetics.
• Modifying surface structure of nanoarchitectures is a promising strategy for enhancing electrochemical performance.

Purpose of the Study:

• To synthesize VS4 microspheres with varying crystallinities.
• To investigate the impact of crystallinity on the electrochemical performance of VS4 as anode materials for sodium-ion batteries (SIBs).

Main Methods:

• Facile template-free hydrothermal synthesis of VS4 microspheres.
• Electrochemical characterization of VS4 electrodes for SIBs.
• Analysis of sodium insertion mechanism and pseudocapacitive behavior.

Main Results:

• Electrochemical performance of VS4 anodes strongly depends on nano-unit crystallinity.
• The VS4 electrode with the lowest crystallinity achieved a high reversible capacity (412 mA h g-1 at 0.2 A g-1 after 230 cycles).
• High capacities were maintained at higher current densities (345 mA h g-1 at 1.0 A g-1, 293 mA h g-1 at 2.0 A g-1).

Conclusions:

• Decreasing VS4 nano-unit crystallinity enhances pseudocapacitive behavior, improving sodium storage.
• This study offers insights into designing high-performance anodes for SIBs by controlling surface structure and crystallinity.