Activated carbon from hazelnut bark-based biomaterial as an electrode material for supercapacitors

The growing demand for sustainable energy storage solutions drives the search for eco-friendly and low-cost electrode materials for supercapacitors. This study presents a sustainable approach for converting discarded hazelnut bark-based biocomposite into activated carbon (AC). The biocomposite was chemically activated with KOH at a mass ratio of 1:3. The mixture was then thermally treated under a nitrogen atmosphere in two stages: initially heated at 2 °C/ min to 500 °C and held for 1 h, followed by heating at 5 °C min⁻¹ to 800 °C with an additional 1 h retention time. Electrochemical performance was investigated by cyclic voltammetry (CV) at various scan rates in 0.5 M H2SO4. The CV curves show a nearly rectangular shape, indicating that the charge storage mechanism is predominantly governed by electric double-layer capacitance. These findings demonstrate that hazelnut bark-based biocomposite represents a sustainable and efficient precursor for producing high-performance activated carbons, offering a promising alternative to conventional electrode materials in supercapacitors and contributing to environmentally responsible energy storage technologies.