Fabrication of High-Performance Asymmetric Supercapacitors Using Rice Husk-Activated Carbon and MnFe₂O₄...

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Growing demand for efficient, cost-effective, and environmentally friendly energy storage solutions.
• Rice husk-activated carbon (RHAC) offers abundance, low cost, and good electrochemical properties.
• MnFe2O4 nanostructures are effective pseudocapacitive materials.

Purpose of the Study:

• To improve the capacitance and energy density of asymmetric supercapacitors (ASCs).
• To explore the synergistic effects of combining RHAC with MnFe2O4 nanostructures.
• To develop a sustainable energy storage solution using agricultural waste.

Main Methods:

• Fabrication of RHAC from rice husk via activation and carbonization.
• Synthesis of MnFe2O4 nanostructures.
• Assembly and electrochemical characterization of ASCs using galvanostatic charge-discharge, cyclic voltammetry, and electrochemical impedance spectroscopy.

Main Results:

• RHAC exhibited a BET surface area of 980 m²/g and an average pore diameter of 7.2 nm.
• The ASC achieved a maximum specific capacitance of ~420 F/g at 0.5 A/g.
• The ASC retained 98% capacitance after 12,000 cycles at 6 A/g, showing high stability and rate capability.

Conclusions:

• The synergistic combination of RHAC and MnFe2O4 nanostructures significantly enhances ASC performance.
• The developed ASC demonstrates high specific capacitance, excellent rate capability, and long-term cycle stability.
• This study presents a sustainable method for energy storage by repurposing agricultural waste.