Simultaneously addressing the formidable challenges of reflection-induced secondary pollution and the limited dynamic range of responsive electromagnetic interference (EMI) shielding remains a critical bottleneck for intelligent electromagnetic protection. Herein, we report a gradient liquid metal hydrogel platform that enables a synergistic, decoupled electronic-ionic switching mechanism to achieve high-contrast and absorption-dominated shielding. Unlike conventional responsive hydrogels that rely on quality-deteriorating solvent exchange, swelling, or shrinking—processes that inherently compromise structural reliability—this platform achieves precise, reversible shielding control without any mass loss or structural deformation. By nanoconfining LM microdroplets within a mechanically robust, aramid nanofiber-reinforced PVA matrix, we develop a unique phase-transition-driven “double-lock” switching mechanism. This mechanism leverages the decoupled sequential phase transitions of the LM fillers (electronic channel) and the ionic solvent (ionic channel) to realize a stable transition between electromagnetic “transparency” and “protection”. Specifically, a biomimetic gradient architecture effectively eliminates surface impedance mismatch, achieving an ultra-high EMI shielding effectiveness (SE) of 60.6 dB with a distinct absorption-dominant characteristic (A/R > 1.2). The synergistic “double-lock” system enables a remarkable dynamic switching contrast of 50.7 dB while maintaining its “green” shielding mechanism throughout all functional operational states. By synergizing this high switching contrast with a consistently absorption-dominated performance whenever active shielding is engaged, this work establishes a structure-driven paradigm for next-generation green and intelligent electromagnetic protection.
Yang et al. (Wed,) studied this question.