Tunnel-Oriented VO₂ (B) Cathode for High-Rate Aqueous Zinc-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Tunnel-type vanadium oxides are key cathode materials for aqueous zinc ion batteries.
• Enhancing ion transport kinetics in fixed-size tunnels is a significant challenge compared to layer-type cathodes.

Purpose of the Study:

• To investigate how macroscopic electrode arrangement influences ion transport in tunnel-type vanadium oxide cathodes.
• To optimize tunnel orientation via material morphology for improved ion diffusion.

Main Methods:

• Fabrication of dispersive (VO2-D) and aggregated (VO2-A) VO2(B) nanobelt morphologies.
• Electrode preparation and electrochemical performance testing (rate capability, cycling stability).
• Analysis of crystal facet orientation and its effect on ion transport pathways.

Main Results:

• Dispersive VO2(B) nanobelts with (00l) facets exhibited directional ion transport along the c-axis.
• VO2-D electrodes showed significantly faster ion diffusion and superior rate performance (420.8 mAh g-1 at 0.1 A g-1) compared to VO2-A.
• Exceptional cycling stability was achieved (84.3% retention after 5000 cycles at 10 A g-1).

Conclusions:

• Macroscopic electrode arrangement is critical for controlling tunnel orientation and ion transport in VO2 cathodes.
• Tailoring material morphology and exposed crystal facets can optimize ion diffusion kinetics.
• This strategy offers a promising pathway for developing high-performance tunnel-type vanadium oxide cathodes for zinc ion batteries.