Flexible fiber-shaped supercapacitors based on graphene/polyaniline hybrid fibers with high energy density and capacitance.

Fiber-shaped supercapacitors (FSCs) are promising energy storage devices for portable and wearable electronics due to their miniaturized size, flexibility, and knittability. Despite the significant progress in this area, it is still a challenge to develop large capacitance and high energy density fiber-shaped supercapacitors for practical applications. In this work, a hybrid fiber composed of reduced graphene oxide and polyaniline nanoparticles (r-PANI-GOF) are synthesized via in-situ deposition of polyaniline nanoparticles on graphene oxide fibers followed by further reduction. The areal specific capacitance of a single r-PANI-GOF electrode is as large as 1755 mF cm-2 in the three-electrode system. The r-PANI-GOF hybrid fibers were also used as electrodes for making an all-solid-state fiber-shaped supercapacitor. This whole device has a specific areal capacitance of up to 481 mF cm-2 and a high areal energy density of 42.76 μWh cm-2. The hybrid fiber electrodes with a high capacitance, long-term stability, and excellent flexibility may become new candidates for the development of fiber-shaped high-performance energy storage devices.