Overlapped T‑Nb2O5/Graphene Hybrid for a Quasi-Solid-State Asymmetric Supercapacitor with a High Rate Capacity

• Published in: Energy & fuels 2021-08, Vol.35 (15), p.12546-12555
• Main Authors: Wu, K. F, Fan, J. H, Wang, X. H, Wang, M. T, Xie, X. F, Fan, J. T, Chen, A. Y
• Format: Article
• Language: English
• Subjects: Batteries and Energy Storage
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/acs.energyfuels.1c00932

To utilize the special intercalation pesudocapacitive behavior of T-Nb2O5 and good conductivity of reduced graphene (rGO), a T-Nb2O5/rGO composite with an overlapping structure is developed to meet the demands of energy storage devices with a remarkable electrochemical performance. T-Nb2O5 nanowires (NWs) prepared by a hydrothermal method are assembled layer by layer onto the GO surface by electrostatic interaction to obtain T-Nb2O5/rGO hybrids. The overlapped T-Nb2O5/rGO composites exhibit an outstanding capacitance of 1492 F g–1 at 1 A g–1, which is superior to that of pure T-Nb2O5 NWs, and also present a better cycling stability of 88.6% of the initial capacitance after 3000 charge–discharge cycles in KOH aqueous solution. The supercapacitive performances of an asymmetric supercapacitor (ASC) of T-Nb2O5/rGO//activated carbon (AC) are evaluated in KOH aqueous solution and a quasi-solid KOH/poly­(vinyl alcohol) gel. The quasi-solid ASC device of T-Nb2O5/rGO//AC delivers an energy density of 72 Wh kg–1 at 479 W kg–1. Furthermore, the ASC device could power a digital timer and a red light-emitting diode upon fast charging, exhibiting potential applications in future portable electronics.