Flexible, lightweight carbon nanotube sponges and composites for high-performance electromagnetic interference shielding

Abstract Flexible, low-density, high-performance electromagnetic interference (EMI) shielding performance materials are urgently required in aerospace and flexible electronic devices. Due to the high aspect ratio and conductivity, carbon nanotube (CNTs) has been considered as one of the most promising candidates for providing excellent EMI shielding performance. Here, a flexible spongy CNTs consisting of self-assembled, interconnected CNT skeletons, with a density of 10.0 mg/cm 3 , was directly used as EMI shielding film. The freestanding CNT sponge with a thickness of 1.8 mm shows highly EMI shielding effectiveness (SE) and specific SE (SSE) of 54.8 dB and 5480 dB cm 3 /g in X-band, respectively. The performance of the CNT sponges can be further improved by increasing the thickness or density of the samples. After composited with PDMS by directly infiltrating method, the CNT/PDMS film still exhibits excellent EMI SE (46.3 dB) at the thickness of 2.0 mm, while the CNT loading content is less than 1.0 wt%. The EMI SE of the composite is almost unchanged after repeated stretching or bending for 1000 cycles. The flexible, stability, and highly conductive nanocompsite can be directly used as high-performance EMI shielding films in areas such as packaging, electronics and communication.