Using adsorption product of reduced graphite oxide for neutral red as bind-free electrode for solid-state supercapacitor

[Display omitted] •RGO was working as adsorbent to adsorb neutral red (NR) from an aqueous solution.•The adsorption product of NR/RGO was used as bind-free electrode for supercapacitors.•NR/RGO electrode gives an impressive specific capacity of 503 F g−1 at 1.0 A g−1.•A symmetrical solid-state supercapacitor based on NR/RGO has been assembled. Graphene-based materials play an important part as adsorbent for dyeing water treatment. However, the following regeneration methods for absorbents remain complex and might generate new polluting contaminants. Exploring the practical application for adsorbents remains a great challenge. Herein, the reduced graphite oxide (RGO) was used as adsorbent for adsorb neutral red (NR) from an aqueous solution, and the adsorption product of NR/RGO was used as binder-free electrode for supercapacitors. The NR/RGO electrode can supply a specific capacitance of 503 F g−1 and excellent cycle stability. Subsequently, the NR/RGO composite is used to assemble a solid-state symmetrical supercapacitor device. The assembled NR/RGO//NR/RGO device provides a moderate specific energy of 39.7 Wh kg−1 at 350 W kg−1 and an outstanding cycle stability. The use of NR/RGO composite as a binder-free electrode for a supercapacitor offers an innovative practical application of adsorption product for the graphene-based adsorbents for dyeing wastewater.