Hybrid composite polyaniline-nickel hydroxide electrode materials for supercapacitor applications

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Development of advanced electrode materials is crucial for improving energy storage devices.
• Polyaniline (PANI) and nickel hydroxide [Ni(OH)₂] are known electrode materials with distinct properties.
• Nanocomposite (NC) hybrid electrodes offer potential for synergistic improvements in electrochemical performance.

Purpose of the Study:

• To prepare and characterize pristine polyaniline (PANI) and PANI-Ni(OH)₂ nanocomposite (NC) hybrid electrodes.
• To investigate the electrochemical performance, reversibility, and stability of these electrodes.
• To compare the properties of NC electrodes with individual PANI and Ni(OH)₂ electrodes.

Main Methods:

• Electrodeposition technique used for fabricating PANI, Ni(OH)₂, and PANI-Ni(OH)₂ NC electrodes on stainless-steel substrates.
• Voltammetric analysis to determine specific capacitance (SC) and charge retention at various scan rates.
• Cyclic stability testing up to 1000 cycles to assess long-term performance.

Main Results:

• Pristine Ni(OH)₂ electrodes showed the highest maximum specific capacitance (113.8 F/g), surpassing PANI (0.59 F/g) and NC electrodes (39.06–32.36 F/g).
• NC electrodes exhibited significantly higher reversibility (52.4–61.1% SC retention) and electrochemical stability (61.5–67.5% SC retention over 1000 cycles) compared to pristine electrodes.
• Analysis of charge contributions indicated distinct roles of inner and outer charge storage sites in the NC electrodes.

Conclusions:

• The PANI-Ni(OH)₂ NC electrodes demonstrate superior reversibility and long-term stability, making them promising for energy storage applications.
• Despite lower maximum capacitance, the enhanced cycling performance and charge retention of NC electrodes highlight their potential.
• The study provides insights into the synergistic effects within hybrid nanocomposite electrodes for electrochemical energy storage.