Hybrid supercapacitors using metal-organic framework derived nickel-sulfur compounds

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Metal-organic frameworks (MOFs) possess high porosity and stable structures ideal for supercapacitor electrode precursors.
• MOFs offer advantages for redox reactions and rapid ion transport in electrochemical energy storage devices.

Purpose of the Study:

• To develop a stable and high-performance supercapacitor electrode material using a Ni-MOF sacrificial template.
• To investigate the electrochemical properties of a carbon-coated Ni9S8 composite (Ni9S8@C-5) for supercapacitor applications.

Main Methods:

• A carbon-coated Ni9S8 composite (Ni9S8@C-5) was synthesized using a spherical Ni-MOF as a sacrificial template via sulfuration at 500 °C.
• A hybrid supercapacitor (HSC) was assembled using Ni9S8@C-5 as the positive electrode and coal pitch-based activated carbon (CTP-AC) as the negative electrode.

Main Results:

• The Ni9S8@C-5 composite exhibited a specific capacity of 278.06 mAh·g⁻¹ at 1 A·g⁻¹, attributed to the stable carbon skeleton and multinuclear Ni9S8 structure.
• The fabricated HSC achieved an energy density of 69.32 Wh·kg⁻¹ at 800.06 W·kg⁻¹ and maintained 83.06% capacity after 5000 cycles at 5 A·g⁻¹.
• The Ni-MOF template method successfully prevented structural collapse and agglomeration of Ni9S8, enhancing electrochemical performance.

Conclusions:

• The Ni-MOF sacrificial template method provides an effective strategy for preparing advanced supercapacitor electrode materials.
• The developed Ni9S8@C-5 composite demonstrates significant potential for high-performance supercapacitors due to its improved structural stability and electrochemical activity.
• This simple preparation technique shows broad applicability for future supercapacitor electrode development.