Mass production of hierarchically porous carbon nanosheets by carbonizing “real-world” mixed waste plastics toward excellent-performance supercapacitors

Abstract Recently, sustainable development and serious energy crisis called for appropriate managements for the large number of municipal and industrial waste plastics as well as the development of low-cost, advanced materials for energy storage. However, the complexity of waste plastics significantly hampers the application of ever used methods, and little attention is paid to the utilization of waste plastics-derived carbon in energy storage. Herein, porous carbon nanosheets (PCNSs) was produced by catalytic carbonization of “real-world” mixed waste plastics on organically-modified montmorillonite (OMMT) and the subsequent KOH activation. PCNSs was featured on hierarchically micro-/mesoporous structures with the pore size distribution centered on 0.57, 1.42 and 3.63 nm and partially exfoliated graphitic layers, and showed a high specific surface area of 2198 m 2  g −1 and a large pore volume of 3.026 cm 3  g −1 . Benefiting from these extraordinary properties, PCNSs displayed a superior performance for supercapacitors with high specific capacitances approaching 207 and 120 F g −1 at a current density of 0.2 A g −1 in aqueous and organic electrolytes, respectively. Importantly, when the current density increased to 10 A g −1 , the specific capacitances remained at 150 F g −1 (72.5%) and 95 F g −1 (79.2%) in aqueous and organic electrolytes, respectively. The outstanding rate capability of PCNSs was in sharp contrast to the performance of traditional activated carbons. This work not only provides a potential way to recycle mixed waste plastics, but also puts forward a facile sustainable approach for the large-scale production of PCNSs as a promising candidate for supercapacitors.