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

In this study, poly( m -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 (V 2 O 5 ), amino-functionalized graphene (amino-FG) and PmAP was fabricated via hydrothermal growth of V 2 O 5 nanoparticles on graphene surfaces and then blending with PmAP/DMSO and solution casting. The electrochemical performances of V 2 O 5 /amino-FG/PmAP nanocomposite were evaluated in two different electrolytes, such as KCl and Li 2 SO 4 , and compared with those of V 2 O 5 /amino-FG nanocomposite with PVDF binder. The cyclic voltametric (CV) results of the V 2 O 5 /amino-FG/PmAP nanocomposite exhibited strong pseudocapacitive responses from the V 2 O 5 and PmAP phases, while the faradaic redox reactions on the V 2 O 5 /amino-FG/PVDF electrode were suppressed by the inferior conductivity of the PVDF. The V 2 O 5 /amino-FG/PmAP electrode delivered a 5-fold greater specific capacitance than the V 2 O 5 /amino-FG/PVDF electrode. Solid-state asymmetric supercapacitors (ASCs) were assembled with V 2 O 5 /amino-FG/PmAP film as a positive electrode, and their electrochemical properties were examined in both KCl and Li 2 SO 4 electrolytes. Although the KCl electrolyte-based ASC has greater specific capacitance, the Li 2 SO 4 electrolyte-based ASC delivers a higher energy density of 51.6 Wh/kg and superior cycling stability.