With the increasingly severe electromagnetic pollution, the demand for
low-reflection electromagnetic interference shielding (EMI) materials has
become progressively urgent. Based on the layered design, the
(MXene@CoFe2O4/waterborne polyurethane
(WPU))-(MXene/WPU)-(MXene@CoFe2O4/WPU) composite aerogels with
sandwich structure (SWCA) are prepared by layer freezing and freeze-drying
method, using WPU as the matrix and heterostructure MXene@CoFe2O4
prepared by solvothermal reduction as electromagnetic filler. When the mass
ratio of MXene to CoFe2O4 is 1:6, MXene@CoFe2O4 exhibits optimal
impedance matching (with the value of |Zin/Z0| closer to 1). Due to the
synergistic effect between the absorbing layer of MXene@CoFe2O4/WPU
aerogels and the reflecting layer of MXene/WPU aerogels, SWCA assembled
with 80 wt.% MXene/WPU aerogels and 40 wt.% MXene@CoFe2O4-3/WPU
aerogels achieve high EMI shielding effectiveness (77 dB) and low reflection
(0.14) in the X band. Besides, SWCA demonstrates dual-sided low-reflection
EMI shielding performance, to the extent that in practical applications, they
are no longer restricted to specific installation directions. Moreover, SWCA
shows high compressive stress (maximum compressive stress of 264.0 kPa at
50% compressive strain), compressive resilience (88% resilience after 100
cycles of compression), excellent thermal insulation (thermal conductivity
between 0.0843 and 0.0941 W (m·K)?1) and infrared camouflage performance.
The multifunctional flexible EMI shielding aerogels with low reflection and
high performance holds great promise for application prospect in
next-generation electronic devices.