Sacrificial MOF-derived MnNi hydroxide for high energy storage supercapacitor electrodes via DFT-based quantum...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Supercapacitors are crucial for clean energy transition due to high capacitance, rapid charge/discharge, and long lifespan.
• Growing demand for efficient and sustainable energy solutions necessitates advanced electrode materials.
• Metal-Organic Frameworks (MOFs) offer a promising platform for synthesizing novel energy storage materials.

Purpose of the Study:

• To synthesize high-performance supercapacitor electrodes using MnNi-MOF-74 as a precursor.
• To investigate the electrochemical properties of bimetallic Mn(OH)₂/Ni(OH)₂ hydroxides with tailored morphologies.
• To explore the potential of MOF-derived materials for high-temperature and durable supercapacitors.

Main Methods:

• Synthesis of bimetallic Mn(OH)₂/Ni(OH)₂ hydroxides (MnNi-x) by treating MnNi-MOF-74 on nickel foam with varying KOH concentrations.
• Characterization of material morphology, surface area, and porosity.
• Electrochemical performance testing (specific capacitance, cycling stability) and Density Functional Theory (DFT) calculations for quantum capacitance analysis.

Main Results:

• MnNi-6 sample exhibited superior performance with a specific capacitance of 4031.51 mF cm⁻² at 2 mA cm⁻², high surface area (186 m²/g), and abundant micropores.
• MnNi-6 demonstrated excellent thermal stability and cycling durability, retaining 86.34% capacity after 10,000 cycles at 10 mA cm⁻².
• DFT calculations confirmed high quantum capacitance in Mn(OH)₂/Ni(OH)₂ with a 3:1 Mn:Ni molar ratio due to favorable electron density near the Fermi level.

Conclusions:

• MOF-derived bimetallic hydroxides are highly effective for developing advanced supercapacitor electrodes.
• The MnNi-6 material shows significant potential for high-performance, durable, and high-temperature supercapacitor applications.
• This research paves the way for novel electrochemical energy storage solutions using tailored MOF-derived materials.