• Aramid nanofiber/MXene-reinforced polyelectrolyte hydrogels achieve absorption-dominated EMI shielding while maintaining relatively high conductivity, overcoming the classical impedance matching trade-off.
• The hydration effect of hydrophilic polar groups induces intermediate water formation, enhancing polarization relaxation and rearrangement under electromagnetic fields, significantly boosting EMI shielding effectiveness.
• The hydrogels exhibit outstanding mechanical performance, exceptional adhesion strength, and reliable strain-sensing capability for monitoring human motions, demonstrating multifunctional potential.
• Electromagnetic wave attenuation was evaluated across X-band and terahertz frequencies, with performance varying by water content state (hydrated, dried, frozen), offering tunable shielding properties.