The challenges of textiles that can generate and store energy simultaneously for wearable devices are to fabricate yarns that generate electrical energy when stretched, yarns that store this electrical energy, and textile geometries that facilitate these functions. To address these challenges, this research incorporates highly stretchable electrochemical yarn harvesters, where available mechanical strains are large and electrochemical energy storing yarns are achieved by weaving. The solid‐state yarn harvester provides a peak power of 5.3 W kg−1 for carbon nanotubes. The solid‐state yarn supercapacitor provides stable performance when dynamically deformed by bending and stretching, for example. A textile configuration that consists of harvesters, supercapacitors, and a Schottky diode is produced and stores as much electrical energy as is needed by a serial or parallel connection of the harvesters or supercapacitors. This textile can be applied as a power source for health care devices or other wearable devices and be self‐powered sensors for detecting human motion.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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Spider silks represent stretchable and contractible fibers with high toughness. Those tough fibers with stretchability and contractibility are attractive as energy absorption materials, and they are needed for wearable applications, artificial muscles, and soft robotics. Although carbon-based materials and poly(vinyl alcohol) (PVA) composite fibers exhibit high toughness, they are still limited in low extensibility and an inability to operate in the wet-state condition. Herein, we report stretchable and contractible fiber with toughness that is inspired by the structure of spider silk. The bioinspired tough fiber provides 495 J/g of gravimetric toughness, which exceeds 165 J/g of spider silk. Besides, the tough fiber was reversibly stretched to-80% strain without damage. This toughness and stretchability are realized by hybridization of aligned graphene oxide/multiwalled carbon nanotubes in a polyurethane matrix as elastic amorphous regions and β-sheet segments of spider silk. Interestingly, the bioinspired tough fiber contracted up to 60% in response to water and humidity similar to supercontraction of the spider silk. It exhibited 610 kJ/ m3 of contractile energy density, which is higher than previously reported moisture driven actuators.

Graphene-based actuators are of practical interest because of their relatively low cost compared with other nanocarbon materials, such as carbon nanotubes. We demonstrate the simple fabrication of graphene oxide (GO)-based fibers with an infiltrated nylon-6,6 polymer by wet spinning. These fibers could be twisted to form torsional actuators and further coiled to form tensile actuators. By controlling the relative twisting and coiling direction of the GO/nylon fiber, we were able to realize reversible contraction or elongation actuation with strokes as high as -80 and 75%, respectively, when the samples were heated to 200 °C. The tensile actuation showed a remarkably little hysteresis. Moreover, this GO/nylon actuator could lift loads over 100 times heavier than itself and generate a stable actuation at high temperatures over the melting point of the polymer. This novel kind of GO-based actuator, which has a multidirectional actuation, has potential for a wide range of applications such as artificial muscles, robotics, and temperature sensing.