NiO Pseudocapacitance and Optical Properties: Does The Shape Win?

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Nickel oxide (NiO) is a promising material for electrochemical energy storage due to its pseudocapacitive properties.
• Optimizing NiO synthesis is crucial for enhancing its performance in supercapacitors.

Purpose of the Study:

• To investigate the impact of alkali and calcination temperature on NiO's capacitive and optical properties.
• To explore the synthesis of NiO nanomaterials with controlled morphology for energy storage.

Main Methods:

• Surfactant-free hydrothermal synthesis of NiO using nickel nitrate with urea or triethylamine (TEA).
• Calcination of NiO samples at 400 °C and 600 °C.
• Characterization using XRD, SEM, nitrogen adsorption, reflectance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge measurements.

Main Results:

• TEA-assisted synthesis produced NiO nanoflowers, while urea-assisted synthesis yielded nanoparticles or nanoslices depending on calcination temperature.
• NiO synthesized at lower temperatures (400 °C) exhibited superior surface area and porosity.
• High specific capacitances of 502 and 520 F g⁻¹ were achieved for nanoflower and nanoparticle NiO, respectively, at 1 A g⁻¹.

Conclusions:

• Lower calcination temperatures are beneficial for achieving high pseudocapacitive performance in NiO.
• The morphology and properties of NiO can be tuned by controlling synthesis conditions and calcination temperature.
• Synthesized NiO shows potential for use in screen-printed electrodes for electrochemical sensing applications.