Recycling low-density polyethylene microplastics into flexible supercapacitors through carbonization and activation processes

Although the use of plastics in various applications provides humanity with enormous convenience, a vast amount of plastic waste is produced, and their transformation into microplastics during their degradation can negatively affect living organisms. Therefore, it is essential not only to collect a large amount of microplastics but also to recycle them. To recycle the microplastics into reusable materials, in this study, microplastics are properly carbonized and activated as carbonized microplastics (C-MP) and activated carbonized microplastics (AC-MP), while they are considered electrodes for flexible supercapacitors (SCs). Particularly, AC-MP shows excellent properties such as a large specific surface area (631.8m2/g). Then, poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT: PSS) is further included to increase the flexibility of SCs. With this, when PEDOT: PSS-AC-MP SCs are prepared, they show excellent specific capacitance of 92.1 F/g at 0.24 A/g, while this is well preserved even after bending and twisting tests as 50.5 and 47.8 F/g at 0.96 mA/g that correspond to 93.6 and 88.8% of their normal state. Even regarding lifespan, that of PEDOT: PSS-AC-MP SCs is as long as 170h after 1000 cycles. It is therefore corroborated that the microplastic-recycled AC-MP electrode induces superior properties, performance, and stability for flexible SCs applicable to wearable devices.