Ambient-pressure-dried cellulose/MXene sediment aerogel for spectra compatible defense and Joule heating

Abstract

Ambient pressure-dried aerogels show great potential in the field of spectra compatible defense, such as integrating electromagnetic interference shielding and infrared stealth, due to their porous structure. However, they face the critical challenge of structural collapse caused by the strong capillary forces generated during solvent evaporation. Herein, MXene sediment (MS) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofiber (TOCNF) were employed to fabricate TOCNF/MS (TMS) aerogels through an ambient pressure drying process assisted by a dual crosslinking strategy of hydrogen bonds and Zr⁴⁺ ionic cross-linking. Notably, Zr⁴⁺ formed a robust cross‑linking network due to its high charge density and multidentate coordination capability, which could effectively resist capillary forces during ambient pressure drying. Moreover, ethanol was introduced to reduce the surface tension of the solvent, thereby further mitigating these capillary forces. The resultant TMS aerogels maintained an intact porous structure after ambient pressure drying, which facilitated multiple reflections and absorptions of electromagnetic waves while suppressing heat transfer. As a result, the TMS aerogel achieved an electromagnetic interference (EMI) shielding effectiveness (SE) of 73.2 dB in the X band, along with efficient shielding performance (>60 dB) in the C and Ku bands. It also exhibited exceptional infrared stealth capability, attributed to the synergy of low infrared emissivity and low thermal conductivity. Furthermore, the TMS aerogel exhibited outstanding Joule heating performance, reaching a response temperature of 106.8 °C under an applied voltage of 2.5 V. This ambient pressure-dried TMS aerogel provides a new way for efficiently utilizing MXene sediment to construct advanced spectra compatible defense materials.