Thermal-buffering phase change microcapsules embedded into MXene aerogels toward synchronous infrared stealth and electromagnetic shielding

Lightweight multifunctional materials capable of mitigating electromagnetic interference (EMI) and infrared radiation are highly desirable for aerospace and military equipment. Conventional MXene aerogels still suffer from temperature rise under transient thermal shock due to their limited heat capacity and relatively high thermal diffusivity. Herein, phase change microcapsules (PCCs) with latent heat absorption capability were introduced into the MXene aerogel framework via ice-templated assembly. The MXene/PCC (MP) aerogels possess a three-dimensional (3D) porous structure with uniformly dispersed PCCs, achieving a low thermal conductivity of 0.0493 W m −1  K −1 . Moreover, the embedded PCCs actively absorb heat through solid-liquid phase transitions, thereby increasing heat capacity (28.38 J g −1  K −1 ) and suppressing thermal diffusivity (0.08 mm 2  s −1 ), effectively delaying heat propagation. By combining porous thermal insulation, phase‐change heat absorption, and low infrared emissivity of MXene, the MP aerogels markedly enhance resistance to transient thermal shock, maintaining a bottom-region temperature up to 9.67 °C lower than that of the MXene aerogel under 120 °C heating. Finally, the 3D conductive MXene network provides continuous electron pathways and interfaces for polarization and multiple reflections, while PCCs effectively absorb heat generated by electromagnetic losses, achieving reflection-dominated EMI shielding of 35.44 dB. By embedding PCCs into the framework of MXene aerogels, the simultaneous construction of a microporous structure and a phase-change skeleton endows the MXene aerogels with excellent infrared stealth and EMI shielding performance, thereby demonstrating their applicability in aerospace and defense fields.