Rational design of active layer configuration with parallel graphene/polyaniline composite films for high-performance supercapacitor electrode.

• A novel active layer configuration with enhanced interfacial effect is proposed. • Reduced graphene oxide film is cut into two for each polyaniline electrodeposition. • The twin composite films are parallelly assembled for supercapacitor electrode. • The electrode displays excellent specific capacitance and cycling stability. • The all-solid-state device exhibits high energy density toward application potential. For the traditional supercapacitors based on the graphene@polyaniline (PANI) film prepared by electropolymerization, the interfacial contact between the graphene substrate and PANI shell plays a vital role in improving the PANI stability and the electrochemical capacitance of the active layer. In this work, we propose a novel strategy that the reduced graphene oxide (RGO) hydrogel film with given size could be divided into two for respective PANI electrodeposition and the two graphene@PANI films are assembled parallelly on carbon cloth to obtain the supercapacitor electrode. Owing to the additional lateral RGO/PANI interface, the resulting electrode delivers a high specific capacitance of 949 F g−1 at 1 A g−1 and 760 F g−1 even at the high current density of 20 A g−1. The corresponding binder-free symmetric supercapacitor device could attain a maximum energy density of 18.2 Wh kg−1 and a maximum power density of 4.75 kW kg−1, with a high capacitance retention of 93.1% after 10000 charge/discharge cycles. These superior properties of the electrodes based on the parallel RGO/PANI films testify the rational design of the active layer configuration for enhanced interfacial effect. This work would provide a novel pathway towards the preparation of high-performance supercapacitor electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]