W-doped VO₂ for high-performance aqueous Zn-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) are promising for safe and low-cost energy storage.
• Development of stable cathodes with fast kinetics and high energy density is crucial for AZIBs.
• Pure vanadium dioxide (VO2) cathodes face limitations in performance for practical applications.

Purpose of the Study:

• To synthesize and characterize tungsten-doped vanadium dioxide (W-VO2) as a cathode material for AZIBs.
• To investigate the impact of W doping on the structural stability and electrochemical kinetics of VO2.
• To evaluate the energy density, rate capability, and cycle life of W-VO2 cathodes in AZIBs.

Main Methods:

• One-step hydrothermal synthesis method for W-doped VO2 (W-VO2) material.
• Structural analysis to confirm W insertion and lattice expansion.
• Electrochemical testing including charge-discharge cycling, rate capability tests, and long-term cycling stability measurements.

Main Results:

• W-VO2 exhibits an expanded lattice spacing and a stabilized structure due to W6+ pre-insertion and W-O bond formation.
• Achieved a high specific capacity of 340.2 mA h g-1 at 0.2 A g-1.
• Demonstrated excellent high-rate capability (186.9 mA h g-1 at 10 A g-1) and long-term cycling stability (76.5% retention after 2000 cycles).

Conclusions:

• W doping significantly enhances the electrochemical performance of VO2 cathodes in AZIBs.
• The W-VO2 cathode offers improved kinetics, high energy density, and superior cycle life compared to pure VO2.
• This W doping strategy provides a viable pathway for developing advanced high-energy and stable cathodes for AZIBs.