Conductive polymer intercalated vanadium oxide on carbon cloth for fast ammonium-ion storage in supercapacitor applications

Abstract

Aqueous energy storage systems based on ammonium-ion (NH4+) as charge carrier have attracted increasing interest owing to their great potential for large-scale application. Developing suitable cathodes (especially binder-free electrodes) for excellent NH4+ storage is still in their infancy. Herein, a binder-free ACC@VPP electrode, activated carbon cloth (ACC) coated by polymer-intercalated vanadium oxide hydrate (VOH), is demonstrated to be an effective cathode to store NH4+ for the first time. The polymer not only expands V-O interlayer space facilitating rapid ion diffusion, but also benefits VPP coated on ACC. The reversible (de)insertion of NH4+ is along with hydrogen-bond fracture/formation between NH4+ and V-O layers, ensuring encouraging electrochemical properties: a high superior capacitance of 511 F·g−1 (170 mAh·g−1) at 0.5 A·g−1 and durable lifetime over 10,000 cycles. The achieved performances exceed the state-of-the-art NH4+-hosting materials. Assembled flexible quasi-solid-state hybrid supercapacitor (QSS HSC) device delivers an areal capacitance of 411 mF·cm−2 and energy density of 3.2 Wh·m−2 at 1 mA·cm−2. The performances of the QSS HSC devices in different deformation, series and parallel states show greatly potential practicability in the wearable energy supply. This contribution elucidates a new view to design binder-free electrodes for high-performance aqueous NH4+-SCs.