Multifunctional high-compaction MWCNT/GNP hybrid buckypaper: Unraveling superior conductivity for broadband EMI shielding and instantaneous Joule heating applications

Abstract

Buckypaper (BP), a self-supporting film of carbon nanotubes (CNTs), is a promising material for flexible electronics, energy storage, and electromagnetic interference (EMI) shielding. However, its practical utility is hindered by CNT aggregation and limited structural integrity. This study introduces hybrid BP, fabricated by integrating multi-walled carbon nanotubes (MWCNTs) with graphene nanoplatelets (GNPs) via vacuum filtration, resulting in a uniformly dispersed, interconnected architecture. The influence of varying GNP content on structure and properties is systematically explored, with a particular emphasis on EMI shielding and Joule heating. At 75 wt% GNP, the hybrid BP achieves optimal performance, demonstrating exceptional electrical (683 % improvement) and thermal (190 % improvement) conductivity, remarkable mechanical flexibility, and enhanced EMI shielding (126 %) and Joule heating (203 %) compared to pure MWCNT BP. These properties are attributed to a compact, multidimensional conductive network formed by well-dispersed MWCNTs. EMI shielding effectiveness is meticulously evaluated across an extensive frequency spectrum, including X-, Ka-, V-, and W-bands, with reflection, absorption, and transmission mechanisms rigorously analyzed through physical and mathematical frameworks. The hybrid BP also exhibits superior Joule heating with stable spatial, temporal, and responsive characteristics. These findings underscore the multifunctional potential of hybrid BP for advanced electronics, thermal management, and EMI shielding solutions.