Precisely Designed Mesoscopic Titania for High-Volumetric-Density Pseudocapacitance.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Surface redox pseudocapacitance offers rapid charging and high power, crucial for energy storage applications.
• Nanostructuring active materials enhances specific capacity but often leads to low volumetric capacity due to poor tap density.

Purpose of the Study:

• To develop a high-density pseudocapacitive material by designing a mesoscale TiO2 structure.
• To overcome the low volumetric capacity limitation of nanomaterials in energy storage.

Main Methods:

• Fabrication of mesoscale TiO2 with controlled mesoporous frameworks and radially aligned channels.
• Characterization of surface area, tap density, and electrochemical performance as a sodium-ion storage anode.

Main Results:

• The mesoscopic TiO2 exhibited a high tap density (1.7 g cm-3) compared to nanoparticles (0.47 g cm-3).
• Achieved maximized gravimetric capacity (240 mAh g-1) and volumetric capacity (350 mAh cm-3) at 0.025 A g-1.
• Demonstrated a commercially comparable areal capacity (2.1 mAh cm-2) at high mass loading (9.47 mg cm-2).

Conclusions:

• The precisely designed mesoscale TiO2 structure serves as a high-density pseudocapacitive model system.
• This mesostructure enables fast sodiation in dense nanostructures, with implications for high-power and fast-charging devices.