Enhancing Zn²⁺ Storage Performance by Constructing the Interfaces Between VO₂ and Co-N-C Layers

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Vanadium oxides are promising cathode materials for aqueous zinc-ion batteries (AZIBs) due to cost and safety.
• Challenges include low ion diffusion and vanadium dissolution, leading to capacity decay and poor cycling stability.

Purpose of the Study:

• To develop enhanced cathode materials for AZIBs by addressing the limitations of vanadium oxides.
• To improve the electrochemical performance and long-term stability of AZIBs.

Main Methods:

• Synthesis of vanadium dioxide (VO2) nanobelts coated with a single-atom cobalt dispersed N-doped carbon (Co-N-C) layer via calcination.
• Characterization using various in-/ex situ techniques.
• Density functional theory (DFT) simulations to investigate interfacial mechanisms.

Main Results:

• The Co-N-C coating protects VO2 nanobelts, enhances ion diffusion, and improves Zn2+ storage.
• Co-O-V bonds at the interface facilitate interfacial Zn2+ storage.
• Achieved ultrahigh capacity (418.7 mAh g-1 at 1 A g-1), excellent long-term stability (>8000 cycles at 20 A g-1), and superior rate performance.

Conclusions:

• The VO2@Co-N-C nanobelts represent a highly effective cathode material for AZIBs.
• The developed strategy offers a pathway for designing advanced energy storage materials.