Facile synthesis of battery waste-derived graphene for transparent and conductive film application by an electrochemical exfoliation method

Abstract

One of the emerging challenges in tackling environmental issues is to treat electronic waste, with fast-growing battery waste as a notable threat to the environment. Proper recycling processes, particularly the conversion of waste to useful & value-added materials, are of great importance but not readily available. In this work, we report a facile and fast production of graphene from graphite extracted from spent Zn–C batteries. The graphene flakes are produced by electrochemically exfoliating graphite under varying DC voltages in poly(sodium 4-styrenesulfonate) (PSS) solution of different concentrations. The exfoliation takes place via the insertion of PSS into the interlayers of graphite to form C–S bonds as confirmed by FTIR and XPS studies. Under an applied voltage of 5 V and in 0.5 M PSS, high quality graphene flakes are obtained in a good yield, giving an I_D/I_G ratio of about 0.86 in Raman spectroscopy. The transparent conductive film prepared from the dispersion of high quality graphene flakes shows great promise due to its low sheet resistance (R_s) of 1.1 kΩ sq⁻¹ and high transmittance of 89%. This work illustrates an effective and low-cost method to realize large scale production of graphene from electronic waste.