Electrochemical performance of bridge molecule-reinforced activated carbon fiber-m-aminobenzenesulfonic acid-polyaniline for braidable-supercapacitor application

Abstract

The bridge molecule-reinforced activated carbon fiber-m-aminobenzenesulfonic acid-polyaniline (ACF-mABSA-PANI) is designed and fabricated as braidable-supercapacitor electrode to achieve long cycle life and high capacitive performance. The mABSA acts as bridge molecule to form amide bond between mABSA and ACF, as well as sulfonamide bond between mABSA and PANI, which is confirmed by infrared spectrometer and X-ray photoelectron spectroscopy. The interfacial interaction between ACF and PANI is enhanced by chemical bonding, thus alleviating the shedding of polyaniline and improving the cycle life of ACF-mABSA-PANI. The electrostatic potential and Mulliken charge analysis calculations indicate that ACF-mABSA-PANI has an extended delocalized π-π conjugation system. The bridge molecule of mABSA improves the free electron migration efficiency between PANI and ACF, leading to an increase in the specific capacitance of ACF-mABSA-PANI. As a result, ACF-mABSA-PANI presents much higher specific capacitance of 599.3F/g at 0.5 A/g and much higher capacitance retention ratio of 93.8 % after 2000 charge/discharge cycles at 2 A/g while ACF-PANI only keeps 335.0F/g and 54.4 %. Braidable-supercapacitor based on ACF-mABSA-PANI electrode provides an energy density of 39.83 Wh kg−1 at a power density of 900 W kg−1 and maintains a high capacitance retention of 78.1 % after 2000 charge/discharge cycles at 2 A/g. Well-designed ACF-mABSA-PANI presents the potential and promising application for wearable electrochemical energy storage devices.