▎ 摘　　要

Recycling electronic wastes (e-wastes) is one of the steps to build greener and cleaner environment. In this work, re-using of disposed dry cell (zinc-carbon battery) components to generate graphene and manganese oxide for energy storage application has been demonstrated. The obtained materials have been characterized by X-ray diffraction, Fourier transformed infrared spectroscopy, Raman spectroscopy and scanning electron microscope. The electrochemical performances of the generated graphene and the MnO2 have been examined in 1M H2SO4. The symmetric (MnO2|PVA:H2SO4|MnO2) and asymmetric (Graphene|PVA:H2SO4|MnO2) supercapacitors were fabricated and their performances were evaluated. The fabricated proto-type asymmetric device delivered energy density as high as 68 W h kg(-1) at power density of 8010 W kg(-1) with a wide operating potential up to 1.6 V. The device had a long life of 5000 cycles with high Coulombic efficiency as high as 90 %. The observed such an excellent electrochemical performances are attributed to the large surface area and high conductivity of the graphene nanonetwork and nanoporous MnO2 extracted from the disposed dry cell. The two asymmetric proto-type devices connected in series could light an LED for about 10 min in one charge.