High energy density electrodes based on solution intercalated, self-stabilised dispersion polymerised polyaniline/MWCNT hybrids for supercapacitors

Abstract

Worldwide technological advancements have stimulated the need for efficient energy storage devices that can deliver high energy and power densities. This can be achieved by incorporating efficient electroactive materials like conducting polymers (CPs) and multi-walled carbon nanotubes (MWCNTs) and adopting different strategies for the preparation of electrodes. Hybrids of CPs with CNTs exhibit synergistic effects and are excellent choices as supercapacitor electrodes. In this work, polyaniline (PANI) is prepared using the self-stabilised dispersion polymerisation (SSDP) method. The PANI/MWCNT hybrid electrodes are prepared using the conventional in-situ method and a unique method that involves secondary doping followed by solution intercalation. The optimised electrode (PCM 1:1) displays a high specific capacitance of 1017 F g−1 at a current density of 0.5 A g−1. A symmetric supercapacitor fabricated using PCM 1:1 electrode delivers an energy density of 46.69 Wh kg−1 at a power density of 1 kW kg−1, one of the best reported values for similar composite materials. The device delivers an energy density of 27.86 Wh kg−1 even at a high-power density of 5 kW kg−1. The symmetric supercapacitor retains 93.3 % of its initial capacitance even after 10,000 continuous charge-discharge cycles at a current density of 5 A g−1. Interestingly, the electrodes and devices fabricated using the hybrid samples prepared by the solution intercalation method outperform those of the in-situ samples. The superior electrochemical performance, cycle stability and improved energy density of this hybrid sample offer ample scope for developing efficient and robust supercapacitors for futuristic energy storage devices.