Metal oxides (MOs) have garnered significant attention in a variety of research fields, particularly in flexible electronics such as wearable devices, due to their superior electronic properties. Meanwhile, polymers exhibit excellent mechanical properties such as flexibility and durability, besides enabling economic solution-based fabrication. Therefore, MO/polymer nanocomposites are excellent electronic materials for use in flexible electronics owing to the confluence of the merits of their components. In this article, we review recent developments in the synthesis and fabrication techniques for MO/polymer nanocomposite-based flexible transistors. In particular, representative MO/polymer nanocomposites for flexible and transparent channel layers and gate dielectrics are introduced and their electronic properties—such as mobilities and dielectric constant—are presented. Finally, we highlight the advances in interface engineering and its influence on device electronics.

Here, we introduce an environmentally friendly way of fabricating carbon nanoparticles which can be utilized as conductive agent for lithium-ion batteries (LIBs). Polyethylene (PE), which comprises the largest portion of plastic waste, was used as a source for carbon nanoparticle synthesis. Sulfonation allowed chemical structural transformation of innately non-carbonizable PE into a carbonizable conformation, and carbon nanoparticles could be successfully derived from sulfonated PE. Then, PE-derived carbon nanoparticles were used as conductive agents for LIBs, and assembled cells exhibited stable performance. Even though the performance is not as good as Super-P, utilization of PE as a source of conductive agent for LIBs might provide an economical advantage to upcycle PE.