Lightweight MXene/carbon composite foam with hollow skeleton for air-stable, high-temperature-resistant and compressible electromagnetic interference shielding

Lightweight electromagnetic interference (EMI) shielding materials with temperature resistant and compressible performance are highly desirable for applications in harsh and complex environment. Herein, we report MXene/carbon composite foam with three-dimensional hollow skeleton structure and low MXene loading by self-assembly and low heating rate (1 °C/min) pyrolysis methods. The composite foam exhibits a density of as low as 5 mg cm−3 with only 3 wt% MXene loading. An average EMI shielding effectiveness (SE) of more than 25 dB over the whole X-band (8.2–12.4 GHz) and more than 30 dB covering the Ku-band (12.4–18 GHz) and the K-band (18–26.5 GHz) with 2 mm thickness are achieved. Benefiting from the low density, the corresponding specific EMI SE (SSE/t) is up to 27300 dB cm2 g−1, which is comparable to or even better than the values of many shielding materials. The foams still display excellent EMI shielding performance after exposure to air in ambient atmosphere (temperature: 25 °C, humidity: ∼30%) for a year or being heated to 210 °C, demonstrating an excellent air stability and temperature resistance. Furthermore, the MXene/carbon composite foam maintains the high EMI shielding performance after 1000 compressing-releasing cycles, demonstrating excellent compressibility.