Upcycling of Polybenzoxazine to Magnetic Metal Nanoparticle-Doped Laser-Induced Graphene for Electromagnetic Interference Shielding

Upcycling carbon materials from waste plastics/resins is of utmost importance but remains challenging. In this work, we reported the production of magnetic metal nanoparticle-doped laser-induced graphene (LIG/M) starting from polybenzoxazine by a combination of drop-casting and laser irradiation. This strategy was applicable to convert various metal complex precursors into nanoparticles, producing diverse LIG/M, where M included Fe3O4, FeCo, and FeNi. Due to the attractive porous structures and electric/magnetic functional characteristics, the obtained LIG/M exhibited a high electromagnetic interference (EMI) shielding effectiveness of 39.1 dB in the X-band for LIG/FeCo. Taking the thickness and lightweight properties into account, the absolute shielding effectiveness of LIG/M is superior to that of the reported metal nanoparticle-doped carbon materials, which demonstrates the advantage of LIG/M as efficient EMI shielding materials. Moreover, the high electrical conductivity and magnetic properties endowed LIG/M with low-voltage-driven electrothermal performance and strong magnetothermal effect. Given the easy-fabrication process and satisfactory performance, the strategy proposed in this work may create propitious opportunities to achieve the high value-added upcycling and reuse of waste plastics/resins with potential applications in various fields, such as EMI shielding, energy storage, and heating systems.