High performance flexible solid-state asymmetric supercapacitor composed of a polyaniline/PEDOT/polyaniline/ultralarge reduced graphene oxide tetralayer film and a PEDOT/MoS2 composite film

A flexible solid-state asymmetric supercapacitor (ASC) was assembled with a polyaniline (PANi)/PEDOT/PANi/ultralarge reduced graphene oxide (UrGO) tetralayer film (denoted as PPPrG, used as the positive electrode) and a PEDOT/MoS2 film (denoted as PMo, used as the negative electrode) on a flexible polyethylene terephthalate (PET) substrate with polyvinyl alcohol/H2SO4 gel electrolyte. The PPPrG tetralayers were fabricated on PET via a layer-by-layer self-assembly method, whereas the PMo electrode was fabricated on PET using a drop-coating approach. The ASC exhibited a maximum energy density of 5.4 mW h/cm(3) at a power density of 110 mW/cm(3), demonstrating excellent electrochemical performance without performance loss despite various deformation states due to high conductivity and flexibility of the multilayer film electrodes, which act as both the active electrode and the current collector. The ASC retained an energy density of 4.0 mW h/cm(3) at a power density of 265 mW/cm(3) with an optimized cell voltage of 0.8 V. The excellent performance of this ASC was ascribed mainly to the conductivity of the multilayer film electrodes, which was improved by the combination of PANi, UrGO and PEDOT layers, which functioned as conducting networks in the nanostructured composite films. This flexible ASC system based on multilayer film electrodes with superior capacitive performance offers substantial promise for use in grid-scale energy storage devices integrated into portable and bio-implantable microelectronic devices.