3D TiO2@Ni(OH)2 Core-shell Arrays with Tunable Nanostructure for Hybrid Supercapacitor Application

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Three-dimensional hierarchical nanostructures are crucial for advanced electrochemical energy storage.
• Titanium dioxide (TiO2) and nickel hydroxide (Ni(OH)2) are key materials in energy storage devices.

Purpose of the Study:

• To synthesize self-supported TiO2@Ni(OH)2 core-shell nanowire arrays for energy storage.
• To investigate the synthesis mechanism and structure-property relationships of these nanostructures.
• To evaluate their performance in hybrid supercapacitors.

Main Methods:

• Hydrothermal synthesis and chemical bath deposition were used to create TiO2@Ni(OH)2 core-shell nanowire arrays on carbon fiber paper.
• The morphology of the Ni(OH)2 shell was tuned by adjusting ammonia concentration.
• Electrochemical performance was assessed using techniques like cyclic voltammetry and galvanostatic charge-discharge.

Main Results:

• Optimized TiO2@Ni(OH)2 core-shell nanostructures exhibited high specific capacities of 264 mAh g(-1) at 1 A g(-1) and 178 mAh g(-1) at 10 A g(-1).
• The synthesis mechanism involves heterogeneous nucleation and oriented crystal growth of the Ni(OH)2 shell.
• An asymmetric supercapacitor prototype using TiO2@Ni(OH)2 as the anode demonstrated high energy and power densities.

Conclusions:

• The study elucidates the structure-property relationship in nanocrystal synthesis for energy storage.
• TiO2@Ni(OH)2 core-shell nanowires present a promising strategy for enhancing battery-type electrodes in hybrid supercapacitors.
• Tunable nanostructure morphology is critical for optimizing electrochemical performance.