Core–Sheath Porous Polyaniline Nanorods/Graphene Fiber-Shaped Supercapacitors with High Specific Capacitance and Rate Capability

Fiber and/or yarn-shaped supercapacitors (FSSCs) have tremendous potential applications in portable and wearable electronics because of their light weight, good flexibility, and weavability. However, FSSCs usually show low energy density, which hinders their wide applications in wearable electronics. It remains challenging for the FSSCs to enhance their energy densities without sacrificing the flexibility and mechanical properties. Herein, we develop a chemical polymerization strategy to fabricate core–sheath porous polyaniline nanorods/graphene fibers which are used as the FSSCs electrode and show excellent electrochemical performances. The assembled polyaniline nanorods/graphene FSSCs exhibit an ultrahigh capacitance of 357.1 mF/cm2, a high energy density of 7.93 μWh/cm2 (5.7 mWh/cm3), and a power density of 0.23 mW/cm2 (167.7 mW/cm3). In addition, the FSSCs show ultralong cycling life (3.8% capacitance loss, 5000 charge–discharge tests), good rate capability (78.9% capacitance retention), and flexibility. The electrochemical performance of polyaniline nanorods/graphene FSSCs exceeds most reported hybrid FSSCs containing conducting polymers and/or metal oxide. This work may pave the way in structure design for portable and wearable energy storage devices.