Synthesis of multilayer graphene from plastic waste for the modification of battery cathode material

Abstract

The widespread production and use of plastics have raised environmental concerns due to their non-biodegradable nature. Effective waste management and conversion of waste into value-added products can be a sustainable solution. This study converts waste plastic into graphene to modify the Nickel–Manganese–Cobalt oxide (NMC) cathode with alumina (Al₂O₃). The Al₂O₃ percentage was varied from 1.0 to 2.0%, with a constant graphene percentage of 6.0%. Extensive analysis using Raman, XRD, FESEM, FTIR, UV-vis, and TGA demonstrated the successful transformation of waste plastic into multilayered graphene with graphitic stacking. The Raman analysis showed an ID/IG ratio of 1.07, which suggests edge defects and limited crystalline domain size, and an I2D/IG ratio less than 1.0 indicates the presence of multilayer graphene nanosheets. A UV absorbance peak at 295 nm in graphene highlights its suitability for optical applications. The thermal stability of graphene up to 600 °C makes it ideal for high-temperature applications. Nanosheet boundaries appear as irregular, overlapping lines or ridges on the surface and are stacked randomly with a crumpled morphology. SEM, FTIR, and XRD characterization of the NMC cathode with 2.0% Al₂O₃ and 6.0% showed better surface quality than other compositions. The charging test results for this cathode show good compatibility with electrodes and a stable interphase. Overall, the results suggest that rapid, large-scale synthesis of high-quality graphene from waste plastics offers significant potential for sustainable graphene production and is viable for future battery research.