Self‐Assembled Construction of Robust and Super Elastic Graphene Aerogel for High‐Efficient Formaldehyde Removal and Multifunctional Application

Simultaneously achieving exceptional mechanical strength and resilience of graphene aerogel (GA) remains a challenge, while GA is an ideal candidate for formaldehyde removal. Herein, flexible polyethyleneimine (PEI) is grafted chemically onto carbon nanotube (CNT) surface, and CNT-PEI@reduced GA (rGA) is fabricated via hydrothermal self-assembly, pre-frozen, and hydrazine reduction process. Introducing CNT-PEI contributes to well-interconnected/robust 3D network construction by connecting reduced graphene oxide (rGO) nanosheets through enhancing cross-linking, while entangled CNT-PEI is intercalated into rGO layers to avoid serious restacking of sheets, producing larger surface area and more formaldehyde adsorption sites. Ultralight CNT-PEI@rGA exhibits extreme high strength (276.37 kPa), reversible compressibility at 90% strain, and structural stability, while FA adsorption capacity reached 568.41 mg g-1 , ≈3.28 times of rGA, derivable from synergistic chemical-physical adsorption effect. Furthermore, CNT-PEI@rGA is ground into powder for first preparing polyoxymethylene (POM)/CNT-PEI@rGA composite, while formaldehyde emission amount is 69.63%/73.96% lower than that of POM at 60/230 °C. Moreover, CNT-PEI@rGA presents outstanding piezoresistive-sensing and thermal insulation properties, exhibiting high strain sensitivity, wide strain detection range, and long-term durability.