MXene@Ag NW cellular composite films were successfully fabricatedviaa potassium ion induction and liquid nitrogen rapid pre-freezing strategy. The film delivers an ultrahigh EMI SE of 81.11 dB and a high thermal conductivity of 19.96 W m⁻¹K⁻¹.

With the rapid advancements of portable and wearable devices, high-efficiency electromagnetic interference (EMI) shielding materials are highly required to eliminate radiated electromagnetic pollution. Ti₃C₂T_x MXene has shown great application potential as an EMI SE material due to its good conductivity. However, a single-loss mechanism has many limitations. Herein, to enrich the electromagnetic-wave-loss ways, MXene@ZIF-67/multiwalled carbon nanotubes (MWCNTs) composite films were successfully prepared by vacuum-assisted filtration, combined with the introduction of magnetic ZIF-67 anchored on MXene by an electrostatic self-assembly method. The MXene@ZIF-67/MWCNTs composite film (MZ₂M₈) achieved the best EMI shielding performance of 63.6 dB at 32 μm thickness, and the contribution ratio of the scattering parameters for absorption to reflection, i.e., SE_A to SE_T, was 66.94%, thus achieving high absorption loss. Due to the high aspect ratio of the MWCNTs and the densely stacked “brick–mortar” layered structure, the composite film also exhibited excellent flexibility and mechanical performance, in which MZ₈M₂ could deliver a high tensile strength of 115.2 MPa, ensuring practical applications in different environments. Moreover, the thermal conductivity of MZ₂M₈ reached 3.367 W m⁻¹ K⁻¹, realizing the synergistic effect of high shielding efficiency and heat-dissipation performance, and avoiding the phenomenon of heat accumulation caused by the conversion of electromagnetic waves into heat energy.

6BaO·xCaO·2Al₂O₃ (x = 0.8, 1.2, 1.6, 2, and 2.2) aluminates were synthesized via a liquid phase co-precipitation method. Effects of the molar amount of CaO on the phase of aluminates before and after melting and their hygroscopic phase, melting properties, environmental stability, evaporation, and emission properties were systematically studied. The results show that with the increase of the molar amount of CaO, the aluminates change from a mixture phase to a single phase of Ba₃CaAl₂O₇, and the diffraction peak shifts to a higher angle. The melted phase of the aluminates changed from a single phase to a mixed phase of Ba₅CaAl₄O₁₂ and Ba₃CaAl₂O₇. Meanwhile, the comprehensive properties of the aluminates are improved. The weight gain of 6BaO·2CaO·2Al₂O₃ aluminates is only 10.88% after exposure to air for 48 h; the pulse emission current density of barium tungsten cathodes impregnated with 6BaO·2CaO·2Al₂O₃ aluminates in the porous tungsten matrix can reach 28.60 A/cm² at 1050 °C, and the evaporation rate is 2.52 × 10⁻¹⁰ g/(cm²·s).