Multi-arches Structured All-carbon Aerogels with Super Elasticity and High Fatigue Resistance as Wearable Sensors.

Compressible and ultralight all-carbon materials are promising candidates for piezoresistive pressure sensors. Although several fabrication methods have been developed, the required elasticity as well as fatigue resistance of all-carbon materials are yet to be satisfied due to energy loss and structure-derived fatigue failure. Herein, we present a two-stage solvothermal freeze-casting approach to fabricate all-carbon aerogel (MGA) with multi-arched structure, which is enabled by the in-depth solvothermal reduction of graphene oxide (rGO) and unidirectional ice-crystal growth. MGA exhibits super compressibility and elasticity, which can resist to an extreme compressive strain of 99% and maintain 93.4% height retention after 100000 cycles at the strain of 80%. Rebound experiments reveal that MGA can rebound the ball (367 times heavier than the aerogel) in 0.02 s with a very fast recovery speed (~615 mm s-1). Even the mass ratio between the ball and aerogel is increased to 1306, the ball can be rebound in a relatively short time (0.04 s) with a fast recovery speed (~535 mm s-1). Due to its excellent mechanical robustness and electrical conductivity, MGA presents stable stress-current response (10000 cycles), tunable linear sensitivity (9.13~7.29 kPa-1) as well as low power consumption (4 mW). The MGA-based wearable pressure sensor can monitor human physiological signals, such as pulses, sound vibrations and muscular movements, demonstrating its potential practicability as wearable devices.