ABSTRACT Developing low‐reflection electromagnetic interference (EMI) shielding materials is essential to mitigate secondary pollution. However, it remains challenging as the high conductivity and permittivity required for strong attenuation inevitably led to severe impedance mismatch and surface secondary reflection. Herein, we transformed low‐value MXene sediment waste into ultralow‐reflection EMI shielding aerogels via a gradient engineering strategy. Specifically, the gradient MXene sediment (GMS) aerogels integrated interfacial polarization and spatial distribution of permittivity, which is achieved by precisely modulating the MXene sediment waste content layer‐by‐layer. Layer‐resolved dielectric characterization confirmed a continuous spatial variation in permittivity, spanning from a low‐permittivity surface to a highly conductive bottom. Electromagnetic simulations further verified that the gradient configuration effectively guides electromagnetic waves into the interior, thereby extending the electromagnetic wave dissipation path and minimizing surface reflection. Consequently, the obtained GMS aerogels delivered a remarkable EMI shielding effectiveness of 77.2 dB coupled with an ultra‐low reflection coefficient (R = 0.07), surpassing most reported magnetic and nonmagnetic counterparts.
Dai et al. (Wed,) studied this question.