Advanced binder-free electrodes based on CoMn₂O₄@Co₃O₄ core/shell nanostructures for high-performance...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Supercapacitors are crucial for energy storage.
• Developing advanced electrode materials is key to improving supercapacitor performance.
• Hierarchical nanostructures offer enhanced electrochemical properties.

Purpose of the Study:

• To design and synthesize novel 3D hierarchical CoMn₂O₄@Co₃O₄ core/shell nanoneedle/nanosheet arrays.
• To evaluate the electrochemical performance of these nanostructures as supercapacitor electrodes.
• To fabricate and test an asymmetric supercapacitor (ASC) using the developed electrode material.

Main Methods:

• Two-step hydrothermal synthesis of CoMn₂O₄@Co₃O₄ core/shell nanoneedle/nanosheet arrays on Ni foam.
• Electrochemical characterization including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.
• Assembly and testing of an asymmetric supercapacitor using CoMn₂O₄@Co₃O₄ as the positive electrode and activated carbon as the negative electrode.

Main Results:

• The hybrid nanostructure exhibited superior capacitive behavior compared to individual components.
• High specific capacitance values of 1627 F g^-1 at 1 A g^-1 and 1376 F g^-1 at 10 A g^-1 were achieved for the electrode.
• The asymmetric supercapacitor demonstrated a specific capacitance of 125.8 F g^-1 at 1 A g^-1, with 89.2% capacitance retention after 5000 cycles, and a high energy density of 44.8 W h kg^-1.

Conclusions:

• The unique CoMn₂O₄@Co₃O₄ nanoarchitecture provides an interconnected pore system beneficial for electrolyte penetration and electron transport.
• The developed hierarchical nanostructures show significant promise as high-performance electrodes for supercapacitors and energy storage applications.