Ultralight and superelastic MXene/reduced graphene oxide aerogels for electromagnetic interference shielding

Lightweight aerogels feature multifunctionality and a high porosity, yet accompanied with poor structure recovery under large strain deformations. In this work, we develop an air bubble-ice crystal dual template and annealing strategy to integrate low density and high resilience for the conductive transition metal carbides/nitrides (MXene) composite aerogels. The air bubbles and ice crystals synergistically exclude the nanosheets to the gas-liquid interfaces, thereby constructing unique Y-shaped junctions and robust skeleton. Subsequent annealing process greatly enhances the lamellar interactions. Under external load, the Y-shaped structures prevent the stress concentration at the junctions by transferring the forces to the skeleton for maintaining structural stability. In addition, the wrinkled and thick cell walls, together with the enhanced interlayer interactions, endow the aerogel with exceptional structural stability and resilience. As a result, the MXene/reduced graphene oxide (RGO) composite aerogels exhibit superelasticity with reversible compressive strains of up to 95%, only with an ultra-low density of 6 mg cm^-3. In addition, the electron bridging effect of the RGO sheets affords the aerogel to deliver excellent electromagnetic interference shielding performance, as high as 46.3 dB at 2.5 mm. Furthermore, the remarkable reshapeability of the aerogels allows for precise regulation of structure and performance (33.5-75.1 dB) by a simple wetting compression process. In summary, this work offers helpful inspirations for developing lightweight and superelasticity aerogels for extensive applications.