Amorphous Mo-Ta Oxide Nanotubes for Long-Term Stable Mo Oxide-Based Supercapacitors.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• High demand for energy storage devices drives research into new materials.
• Molybdenum trioxide (MoO3) shows potential for supercapacitors due to high charge density.
• Poor electrochemical stability of MoO3 in aqueous electrolytes limits its practical application.

Purpose of the Study:

• To overcome the poor electrochemical stability of MoO3 in supercapacitive devices.
• To develop a method for enhancing the stability of MoO3-based electrodes.
• To investigate the role of tantalum oxide in stabilizing MoO3.

Main Methods:

• Fabrication of amorphous molybdenum oxide/tantalum oxide nanotubes via anodic oxidation of a Mo-Ta alloy.
• Characterization of the material's structure and electrochemical properties.
• Long-term cycling tests to evaluate stability.

Main Results:

• Formation of stable amorphous molybdenum oxide/tantalum oxide nanotubes.
• Inclusion of critical tantalum oxide content (>20 at. %) prevents MoO3 electrochemical decay.
• No measurable capacitance loss observed after 10,000 charging/discharging cycles.

Conclusions:

• Amorphous molybdenum oxide/tantalum oxide nanotubes offer excellent electrochemical stability for supercapacitors.
• Tantalum oxide acts as a protective agent for the MoO3 phase.
• This approach enables practical application of MoO3 in high-capacitance energy storage devices.