Superstructured NiMoO₄@CoMoO₄ core-shell nanofibers for supercapacitors with ultrahigh areal capacitance.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Achieving high areal capacitance in supercapacitor electrodes is challenging due to the need for high mass loading and efficient material utilization.
• Existing materials like cobalt molybdate (CoMoO4) and nickel molybdate (NiMoO4) face limitations in maximizing performance for practical applications.

Purpose of the Study:

• To synthesize a novel superstructured material combining NiMoO4 and CoMoO4 for enhanced supercapacitor electrode performance.
• To investigate the synergistic effects of NiMoO4 and CoMoO4 in a core-shell nanofiber array architecture.

Main Methods:

• Fabrication of superstructured NiMoO4@CoMoO4 core-shell nanofiber arrays (NFAs) on a molybdenum-transition-layer-modified nickel foam (NF) current collector.
• Electrochemical characterization of the synthesized material in a 2 M KOH electrolyte to evaluate capacitance and performance.

Main Results:

• The NiMoO4@CoMoO4 NFAs demonstrated a high gravimetric capacitance of 1,282.2 F/g at a mass loading of 7.8 mg/cm2.
• Achieved an unprecedented ultrahigh areal capacitance of 10.0 F/cm2, exceeding previously reported values for individual NiMoO4 and CoMoO4 electrodes.
• The synergistic combination of conductive CoMoO4 and electrochemically active NiMoO4 contributed to the enhanced performance.

Conclusions:

• The developed superstructured NiMoO4@CoMoO4 core-shell nanofiber arrays offer a promising new material for high-performance supercapacitor electrodes.
• This work provides a strategic approach for designing electrodes with superior areal capacitances, paving the way for advanced energy storage solutions.