Enhanced lithium storage performance of V₂O₅ with oxygen vacancy

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Vanadium pentoxide (V2O5) is a promising cathode material for lithium-ion batteries.
• Improving the electrochemical performance and stability of V2O5 is crucial for advanced energy storage applications.

Purpose of the Study:

• To synthesize orthorhombic phase V2O5 nanosheets with high V4+ content (V-V2O5).
• To evaluate the electrochemical performance of V-V2O5 as a cathode active material for lithium-ion batteries.

Main Methods:

• Sol-gel method, freeze-drying technology, and vacuum annealing were employed for material synthesis.
• X-ray photoelectron spectroscopy (XPS) was used to determine the V4+ content.
• Electrochemical performance was assessed using lithium-ion battery testing.

Main Results:

• V-V2O5 nanosheets with 7.4% V4+ content were successfully synthesized, higher than 4.7% in air-annealed V2O5.
• The V-V2O5 cathode exhibited superior cycling stability and higher lithium storage capacity compared to air-annealed V2O5.
• Specific capacities of 224.7 mAh g-1 (V-V2O5) vs 199.2 mAh g-1 (V2O5) after 100 cycles at 200 mA g-1 were recorded.
• Specific capacities of 150 mAh g-1 (V-V2O5) vs 136.7 mAh g-1 (V2O5) after 200 cycles at 3 A g-1 were recorded.

Conclusions:

• The synthesized V-V2O5 nanosheets demonstrate enhanced electrochemical properties for lithium-ion battery applications.
• The high V4+ content contributes to improved cycling stability, lithium storage activity, and reduced electrochemical resistance.
• Vacuum annealing is an effective strategy to enhance the performance of V2O5-based cathode materials.