Ultralight GO-Hybridized CNTs Aerogels with Enhanced Electronic and Mechanical Properties for Piezoresistive Sensors

Extremely low density carbon nanotubes/graphene hybrid aerogels (CNG) are highly potential active materials for fabricating flexible devices, owing to synergistic effects with one (nanotubes) and two (graphene) dimensional characters in a single structure. However, conquering the long-standing dilemma among low electronic conductivity and inferior mechanical properties for CNG remains a challenging task. Here, an ultralight CNG aerogel (1.52 mg cm^-3) with prominent electronic conductivity and mechanical resilience is facilely fabricated through a triple roles design of the sodium dodecyl sulfate (SDS), namely anchoring metal ions, dispersing carbon nanotubes, and inducing self-assembly. It is demonstrated that the Ba²⁺ can be effectively anchored into the GO interlayers by coupling it with the SDS to reinforce the intersheet interactions, thereby achieving remarkable improvement in mechanical properties (Young's moduli up to 18.3 kPa). Density functional theory calculations reveal that the anchored Ba²⁺ acting as molecular bridges can availably reduce the tunneling barrier between the GO sheets and facilitate the multidirectional and fast transport of electronics, inducing the high electrical conductivity of CNG (12.55 S cm^-1). Taking advantage of these features, potential applications in flexible sensing devices have been demonstrated utilizing the remarkable CNG as an active material, giving extraordinary sensing performance including high sensitivity (48.6 kPa^-1), ultralow detection limit (10 Pa), and ultrafast response (18 ms).