H-CoNiSe₂/NC dodecahedral hollow structures for high-performance supercapacitors.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Transition metal selenides are promising for supercapacitors but suffer from poor conductivity and volume expansion.
• Developing advanced electrode materials is crucial for high-capacity energy storage.

Purpose of the Study:

• To synthesize a novel cobalt-nickel selenide nitrogen-doped carbon composite (H-CoNiSe2/NC) for supercapacitor applications.
• To address the conductivity and volume expansion issues in transition metal selenides.

Main Methods:

• Utilized ZIF-67 as a precursor to synthesize hollow polyhedral H-CoNiSe2/NC composite structures.
• Embedded CoSe2 and NiSe2 nanoparticles within a nitrogen-doped carbon framework.

Main Results:

• The H-CoNiSe2/NC electrode exhibited a high specific capacity of 1131 C/g at 1.0 A/g with 90.2% capacity retention after 6000 cycles.
• The H-CoNiSe2/NC//AC hybrid supercapacitor achieved an ultrahigh energy density of 81.9 Wh/kg at 900 W/kg with 92.1% capacitance retention.

Conclusions:

• The synthesized H-CoNiSe2/NC composite effectively enhances conductivity and mitigates volume expansion for superior supercapacitor performance.
• This study presents a viable high-capacity electrode material for next-generation energy storage devices.