Hierarchical honeycomb graphene aerogels reinforced by carbon nanotubes with multifunctional mechanical and electrical properties

Graphene aerogels are a promising candidate as multifunctional compressible materials to translate mechanical deformations into electrical signals for a wide range of applications. However, it remains challenging to achieve various desirable properties simultaneously. Here, we demonstrate hierarchical honeycomb graphene aerogels (GCNTAs) reinforced by functionalized carbon nanotubes using a hydrothermal reduction, two-step freezing, and thermal annealing method. The synergic effects of graphene and carbon nanotubes provide GCNTAs with a wide range of outstanding mechanical and electrical properties: low density (15 mg cm⁻³), high compressive strength of 73.9 kPa at 50% strain, 95.4% strength recovery after 300 compressing cycles, excellent temperature-invariant elasticity and creep resistance, a wide temperature tolerance window from −196 to 900 °C, high electrical conductivity (3.27 S m⁻¹) and superb electromechanical sensing ability. The optimized GCNTA was also applied in a sensor to capturing human movements. Overall, our results show that GCNTAs have excellent application potentials in flexible and wearable electronics.