MXene-enabled induced-current regulation to amplify eddy-current loss in liquid metal composites for efficient microwave absorption

Liquid metals (LMs) exhibit high electrical conductivity and can sustain strong eddy currents under alternating electromagnetic fields, endowing them with intrinsic potential for microwave absorption. However, excessive conductivity leads to severe skin effect, which confines induced currents to surface regions, suppresses volumetric interaction, and causes impedance mismatch, fundamentally limiting absorption efficiency. Herein, an interface-mediated discretization strategy (induced-current regulation) is proposed to regulate eddy-current behavior in liquid-metal-based absorbers. Gallium-based LM droplets were uniformly anchored onto Ti₃C₂Tₓ MXene nanosheets via silane-assisted coordination to form stable LM@MXene core–shell hybrids, which were assembled into oriented LM@MXene@PDMS composites by directional ice templating and vacuum-assisted infiltration. Guided by Faraday’s law of induction, direct LCR-based inductive measurements validated the eddy-current regulation, revealing enhanced eddy-current contributions associated with engineered current pathways. Subsequent electromagnetic analyses, including invariant eddy-current coefficients and negligible magnetic hysteresis, confirmed that the dominant attenuation stems from artificial magnetic loss driven by eddy currents rather than intrinsic magnetism. As a result, the optimized composite achieves a minimum reflection loss of -52.11 dB and an effective absorption bandwidth of 6.1 GHz at a thickness of 2.0 mm. This work establishes induced-current regulation as an effective paradigm for overcoming the skin-depth limitation in high-performance conductive microwave absorbers.