Nitrogen-Doped Carbon from Waste Cardboard Recycling for Electric Double-Layer Capacitors

Carbon is one of the most promising electrode materials in supercapacitors, particularly in Electric Double-Layer Capacitors (EDLCs). Recently, research on the fabrication of carbon materials has focused on environmentally friendly methods for recycling waste and minimizing the use of chemicals. In this study, waste cardboard and hexamethylenetetraamine (HMTA) were used as a carbon and nitrogen source, respectively for an electrode. First, the cardboard was carbonized at 600 degrees C under a nitrogen gas atmosphere. The carbonized materials mixed with nitrogen source, HMTA and were annealed at 350 degrees C in air to achieve surface activation and nitrogen doping. The prepared sample showed a high surface area due to the etched surface, and nitrogen doping was detected by energy dispersive X-ray spectroscopy. The nitrogen-doped carbon electrode showed a good capacitance of ca. 120 F/g at 1 A/g compared to pure carbonized materials. In addition, the performance of the nitrogen-doped carbon electrode was dependent on the nitrogen content in the carbon material.