A mechanically strong and sensitive CNT/rGO–CNF carbon aerogel for piezoresistive sensors

Compressible carbon materials hold great promise for application in various wearable or flexible electronic devices because of their low density, chemical and thermal stability, and high electrical conductivity. However, it is a great challenge to fabricate a carbon material with excellent mechanical performance and high sensitivity due to the brittleness of carbon. In this work, we fabricate a high-performance and lightweight CNT/rGO–CNF carbon aerogel by two key strategies: (1) forming continuous and ordered wave-shaped rGO layers and (2) reinforcing the carbon layers. It is found that cellulose nanofibers (CNFs) play a very important role in enhancing the interaction of rGO and CNTs, while CNTs give rise to strong yet flexible wave-shape layers. Benefiting from the synergistic effect of CNTs and CNFs, the carbon aerogel exhibits ultrahigh compressibility (up to 95% strain), superior elasticity (94.6% height retention for 50 000 cycles), high sensitivity, and an ultralow detection limit for pressure (0.875 Pa). These advantages make it an excellent candidate for fabricating flexible wearable electronic devices for biosignal detection.