Facile Preparation of a Lightweight and Ultra-Thin Nonwoven Carbon Fiber Film with Excellent Electromagnetic Interference Shielding Performance

In this work, a porous, ultra-thin, mechanically strong, and flexible non-woven carbon fiber structured film (NCFF) was fabricated, which exhibited excellent electromagnetic interference (EMI) shielding performance. More specifically, a non-woven raw paper precursor was first constructed by using the wet paper-making method from the short-cut carbon fibers. Afterward, the consecutive procedures of resin impregnation and heat press were applied to obtain NCFF. The morphology, porosity, mechanical properties, and EMI shielding performance of the proposed NCFF were thoroughly investigated to examine the impact of resin concentration and compression pressure. Furthermore, electroless nickel (Ni) plating was also conducted on the optimized NCFF structure to further improve the EMI shielding performance. From the acquired results, it was demonstrated that the optimal NCFF with a thickness value of only 95 μm and a tensile strength of 83.98 MPa (X direction)/47.37 MPa (Y direction) was achieved by using the resin concentration of 15 wt% and the compression pressure of 1.5 MPa. Moreover, the proposed film exhibited excellent EMI shielding effectiveness (EMI-SE) of 40.97 dB, whereas the EMI-SE of the Ni-plated NCFF composite was significantly improved to 79.33 dB. Both films demonstrated also low density in conjunction with excellent electrical conductivity, mechanical strength, and EMI shielding performance at a much thinner thickness compared with the other lightweight electromagnetic shielding materials reported in the literature. As a result, a wide application prospect in aviation, aerospace, telecommunications, and military industries was proved by the proposed material configuration.