Interconnected 3D TiO₂ Nanoscaffolds from TiN Anodization Exhibiting Fast and Reversible Aqueous Cation Insertion

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Titanium dioxide (TiO2) is a crucial material in various electrochemical applications.
• Developing nanostructured TiO2 with high surface area and conductivity is essential for improved performance.
• Existing fabrication methods often face limitations in achieving controlled nanostructures and pore networks.

Purpose of the Study:

• To fabricate TiO2 nanoscaffold thin films with interconnected 3D nano-structures and an ordered pore network.
• To investigate the formation mechanism of these nanoscaffolds during anodization.
• To evaluate the electrochemical properties, including surface area and charge retention, of the fabricated films.

Main Methods:

• Fabrication of TiO2 nanoscaffold thin films via anodization of titanium nitride (TiN) in fluoride-less aqueous electrolytes.
• Characterization of film morphology, pore structure, and interconnections using electron microscopy.
• Electrochemical testing to assess volumetric surface area enhancement and charge retention capacity with various ions (Li+, Na+, K+, Mg2+).

Main Results:

• Successfully fabricated TiO2 nanoscaffold films with ordered pore networks (2-10 nm) and interconnected 3D nano-structures.
• Achieved a significant volumetric surface area enhancement of 540x per micron thickness.
• Demonstrated high charge retention capacity in both nonaqueous and aqueous electrolytes for multiple ions.
• Observed N2 gas release facilitating pore formation and Ti oxidation creating mesh-like structures.

Conclusions:

• The anodization of TiN offers a viable route to create high-performance TiO2 nanoscaffolds.
• The unique nanostructure provides excellent electronic conductivity and electrolyte accessibility, leading to enhanced electrochemical performance.
• These TiO2 nanoscaffold films are promising for diverse electrochemical applications, with potential for patterned structure formation.