Metal oxide heterostructures as multifunctional electrode materials for battery-type supercapacitors and oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing efficient electrode materials is crucial for advancing electrochemical energy storage and electrocatalysis.
• Bismuth oxide (Bi₂O₃) and cobalt oxide (Co₃O₄) are promising materials individually, but their synergistic combination in heterostructures can enhance performance.

Purpose of the Study:

• To synthesize pristine Bi₂O₃, Co₃O₄, and Bi₂O₃/Co₃O₄ heterostructures.
• To evaluate their electrochemical energy storage and electrocatalytic properties.
• To investigate the potential of Bi₂O₃/Co₃O₄ heterostructures as electrode materials for supercapacitors and oxygen evolution reactions.

Main Methods:

• Synthesis of Bi₂O₃, Co₃O₄, and Bi₂O₃/Co₃O₄ heterostructures.
• Electrochemical characterization including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.
• Electrocatalytic testing for oxygen evolution reaction (OER) in alkaline and neutral media.
• Stability tests using chronoamperometry.

Main Results:

• The Bi₂O₃/Co₃O₄ heterostructure achieved a high specific capacitance of 2998 F g^-1 at 1 A g^-1 in battery-type supercapacitors.
• An asymmetric supercapacitor device using Bi₂O₃/Co₃O₄ exhibited a capacitance of 237 F g^-1 at 2 A g^-1 with an energy density of 32.97 Wh kg^-1.
• The Bi₂O₃/Co₃O₄ catalyst demonstrated enhanced oxygen evolution reaction rates with low overpotentials (464 mV in alkaline, 153 mV in neutral media).
• Fast electrode kinetics, high active site density, and long-term stability were confirmed.

Conclusions:

• The synergistic interaction in Bi₂O₃/Co₃O₄ heterostructures significantly enhances electrochemical performance.
• These heterostructures are promising candidates for high-performance supercapacitors and efficient electrocatalysts for oxygen evolution.
• The findings highlight the potential of Bi₂O₃/Co₃O₄ for energy storage and generation applications.