Confined dissipation cage in dual-shell structured Ti3C2Tx@CNTs/Ni hollow spheres for lightweight and broadband electromagnetic wave absorption

Abstract

Ti3C2Tx can dissipate energy well due to its high conductivity, but at the expense of severe electromagnetic (EM) wave reflection, which is exacerbated by self-stacking. Despite various attempts to tackle this problem, the excessive isolation of Ti3C2Tx and massive high-density inorganic components render these designs unfavorable for lightweight and broadband absorption. Meanwhile, improvements in absorption performance are related to active surface and polarization interface expansion, as well as conductive path reconstruction, but the main contributing factor remains unknown. In this work, the dual-shell structured Ti3C2Tx@CNTs/Ni-HS (hollow sphere) composites are fabricated. This structure creates a confined dissipation cage, where the CNTs/Ni shell confines the electron transfer among spheres and prevents self-restacking and the tightly contacted Ti3C2Tx shell forms an uninterrupted conductive path for effective dissipation. Therefore, Ti3C2Tx@CNTs/Ni-HS-1 exhibits a broad effective absorption band of 6.1 GHz and a minimum reflection loss of −64.6 dB at a mass ratio of only 15 wt%. Importantly, when hollow structure cracks, although large active surface and polarizable interface remain, the absorption capacity of fragmented Ti3C2Tx@CNTs/Ni-HS-1 deteriorates, indicating rational conductive path in confined dissipation cage is the main factor in achieving excellent performance. This work provides new insight for the rational design of high-performance absorbers.