Activated Biocarbon from Paper Mill Sludge as Electrode Material for Supercapacitors: Comparative Performance...

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Paper mill waste sludge presents a significant disposal challenge.
• Valorization of industrial waste into functional materials is crucial for a circular economy.

Purpose of the Study:

• To convert South African paper mill waste sludge into activated biocarbon for energy storage applications.
• To investigate the electrochemical performance of the synthesized biocarbon material.

Main Methods:

• A two-step synthesis involving hydrothermal carbonization and NaOH activation at 700 °C.
• Characterization of the biocarbon's porosity and surface area (1139 m²/g).
• Electrochemical testing using three- and two-electrode cells in neutral and alkaline electrolytes.

Main Results:

• High specific capacitance values (up to 206 Fg⁻¹ in neutral electrolyte).
• Good energy densities (up to 21.1 Wh kg⁻¹).
• Excellent capacity retention (up to 92% after 5000 cycles).

Conclusions:

• Activated biocarbon derived from paper sludge is a promising material for electrochemical energy storage.
• The study highlights the potential of the pulp and paper industry in contributing to green energy transition.
• Electrolyte concentration significantly impacts specific capacitance, offering avenues for optimization.