Fabrication of Flexible Poly(-aminophenol)/Vanadium Pentoxide/Graphene Ternary Nanocomposite Film as a Positive Electrode for Solid-State Asymmetric Supercapacitors.

In this study, poly(-aminophenol) (PmAP) has been investigated as a multi-functional conductive supercapacitor binder to replace the conventional non-conductive binder, namely, poly(vinylene difluoride) (PVDF). The kye benefits of using PmAP are that it is easily soluble in common organic solvent and has good film-forming properties, and also its chemical functionalities can be involved in pseudocapacitive reactions to boost the capacitance performance of the electrode. A new ternary nanocomposite film based on vanadium pentoxide (VO), amino-functionalized graphene (amino-FG) and PmAP was fabricated via hydrothermal growth of VO nanoparticles on graphene surfaces and then blending with PmAP/DMSO and solution casting. The electrochemical performances of VO/amino-FG/PmAP nanocomposite were evaluated in two different electrolytes, such as KCl and LiSO, and compared with those of VO/amino-FG nanocomposite with PVDF binder. The cyclic voltametric (CV) results of the VO/amino-FG/PmAP nanocomposite exhibited strong pseudocapacitive responses from the VO and PmAP phases, while the faradaic redox reactions on the VO/amino-FG/PVDF electrode were suppressed by the inferior conductivity of the PVDF. The VO/amino-FG/PmAP electrode delivered a 5-fold greater specific capacitance than the VO/amino-FG/PVDF electrode. Solid-state asymmetric supercapacitors (ASCs) were assembled with VO/amino-FG/PmAP film as a positive electrode, and their electrochemical properties were examined in both KCl and LiSO electrolytes. Although the KCl electrolyte-based ASC has greater specific capacitance, the LiSO electrolyte-based ASC delivers a higher energy density of 51.6 Wh/kg and superior cycling stability.