Core-shell liquid metal/MXene architectures enabled by interface engineering for enhanced microwave absorption

An electrostatic–driven self–assembly strategy was employed to fabricate LM@MXene core–shell composites for EMW absorption. • The LM@MXene composites exhibit excellent processability and colloidal stability. • The optimized absorber delivers excellent performance with an RL min of −62.91 dB and an EAB of 3.52 GHz. • The electromagnetic–wave absorption performance was enhanced by polarization loss due to the formation of LM and MXene heterogeneous interfaces. The rapid proliferation of high-frequency electronic devices demands high-performance electromagnetic wave (EMW) absorbing materials. As an emerging functional filler, liquid metal (LM) has demonstrated significant potential for microwave absorption. However, the inherent high surface tension and fluid nature of LM pose substantial challenges to achieving structural stability and processability, making the construction of robust LM-based architectures a formidable task. Herein, an electrostatic‑driven self‑assembly strategy was adopted to fabricate LM@MXene core‑shell composites for electromagnetic‑wave absorption via activating the liquid‑metal surface, which generates active cations to trigger the spontaneous assembly of MXene nanosheets. As a result, the LM@MXene composites exhibit excellent microwave absorption performance: the minimum reflection loss (RL min ) reaches − 62.91 dB at ultrathin thickness of 1.0 mm, and a maximum effective absorption bandwidth (EAB max ) of 3.52 GHz at the thickness of 1.1 mm. The outstanding electromagnetic absorption performance was primarily dominated by polarization loss and conduction loss. Specifically, the multi-level conductivity gradients across the LM core, the native oxide layer, and the MXene shell induce pronounced charge accumulation and relaxation at these heterogeneous interfaces. Thus, this composite structural design provides a potential route for fabricating high-performance EMW-absorbing materials.