Upcycling of waste printed circuit boards into metallic pyrolytic carbon for supercapacitor electrode

Upcycling of electronic waste is the efficient strategy to minimize the negative effect on environment. In the present study, e-waste (originating from small household appliances) was upcycled into the metal contented pyrolytic carbon (C-WPCB) through a simple pyrolysis without activation or any other additional processes. After crushing and fractionating, pyrolysis was performed at 500 °C under nitrogen atmosphere. The obtained metallic pyrolytic carbon was characterized by well-known techniques such as SEM–EDS, XRF, XRD, ATR/FT-IR, TG/DTG, and BET analyses and utilized for supercapacitor electrode preparation. For this purpose, nickel foam was electrochemically coated by C-WPCB which was previously dispersed in three different solutions: 1.5 M H₂SO₄, 3 M KCl, and 1.5 M KOH, respectively. Electrochemical characterization of the prepared electrodes was performed by cyclic voltammetry (CV) at different scan rates and galvanostatic charge–discharge (GCD) methods at different current densities in 6 M KOH electrolyte in half-cell configuration. The best performance was obtained for the electrode prepared in H₂SO₄ solution where the specific capacitance, specific power, and specific energy were found as 39.5 F/g, 25.0 kW/kg, and 16.5 Wh/kg at 5 A/g, respectively.