Maximized Internal Scattering in Heterostack Ti3C2T x MXene/Graphene Oxide Film for Effective EMI Shielding

Two-dimensional (2D) MXenes have attracted significant attention in electromagnetic interference (EMI) shielding applications due to their unique properties, such as excellent metallic conductivity, high surface area, 2D geometry, tunable surface chemistry, and solution processability. In this study, we present a simple and versatile way for introducing multiple internal interfaces into the Ti3C2T x MXenes using insulating graphene oxide (GO) intercalants to enhance internal scattering, resulting in improved absorption loss and EMI shielding effectiveness (SE). Amine-functionalized MXene flakes exhibit a positive surface charge, while GO flakes have a negative charge at acidic pH levels. The functionalized MXene and GO flakes electrostatically self-assemble to form 2D/2D heterostack of MXene/GO nanosheets, and simultaneously generate multiple internal interfaces with significant impedance mismatch. The 2D/2D alternating heterostack of MXene/GO enhances the internal scattering of incident EM waves. Interestingly, despite their inferior electrical conductivity, the MXene/GO heterostack films exhibit higher EMI SE values than the randomly mixed hybrid films, and even outperform pristine MXene with larger electrical conductivity. This enhancement is attributed to enhanced absorption of electromagnetic waves resulting from strong internal scattering at the multiple internal interfaces in the heterostack film.