High-performance fiber-shaped supercapacitors using carbon fiber thread (CFT)@polyanilne and functionalized CFT electrodes for wearable/stretchable electronics

Fiber-shaped supercapacitor (FSC) is a promising energy storage device for wearable/stretchable electronics by virtue of its unique features such as high flexibility, knittability, small-size and lightweight. However, the energy density of most FSC devices is limited by the relatively low operating voltage. Herein, we develop a solid-state asymmetric fiber-shaped supercapacitor made of carbon fiber thread@polyaniline and functionalized carbon fiber thread electrodes with high operating voltage (1.6 V). The as-prepared device shows a volumetric energy density up to 2 mWh cm(-3) which is higher than/compatible to most reported FSCs. The maximum power density of the device is 11 W cm(-3), which is comparable to typical commercial supercapacitors. Other than good rate capability, long cycle life and high volumetric capacitance, the proposed device has excellent flexibility. It can be embedded in a glove using a traditional weaving technology without degrading its capacitive performance at various bending conditions. To demonstrate the potential of our supercapacitor for stretchable electronics, we incorporate the device into a conventional elastic thread to form a stretchable supercapacitor. The capacitance of the stretchable device is well maintained even after stretching up to 100%, demonstrating its excellent stretchability. These promising results demonstrate the proposed supercapacitor has great potential as an efficient storage device for flexible and wearable electronics applications. (C) 2014 Elsevier Ltd. All rights reserved.