Preparation of quinone modified graphene-based fiber electrodes and its application in flexible asymmetrical supercapacitor

The flexible graphene fiber-based symmetic supercapacitors are usually greatly expected to power small wearable electronics because of their many potential applications. In the present work, the organic electrochemically active material of quinone for asymmetric supercapacitors has been introduced to decorate graphene oxide nanosheets as negative electrodes via a facile hydrothermal self-assembly method. Fortunately, 1,4-naphthoquinone (NQ) is a suitable choice for functionalizing graphene-based materials through noncovalent interactions. Different from conventional quinone based materials, we study naphthoquinone modified electrode materials with satisfactory electrochemical properties, and take the lead in preparing fibrous quinone based electrodes, which are applied to the construction of wearable flexible supercapacitors. As a consequence, the modified NQrGO/CF exhibits an improved capacitance owing to the superposition of capacitance behavior and the synergistic effect of each component. More interestingly, the all-solid asymmetric flexible micro-supercapacitor (AFSC) assembled with NQrGO/CF as the negative electrode, nickel-cobalt hydroxide hybrid graphene-based fiber (NCHrGO/CF) as the positive electrode and PVA/KOH as the gel electrolyte, which has a potential window of 2.0 V, with a maximum energy density of 50.7 Wh kg(-1). Moreover, we propose the multiple microsupercapacitors could be reasonably connected in series or in parallel for the reduction of resistance and the promotion of electrochemical performance to meet the requirements of specific operating voltage and energy output in application. The graphene-based fiber electrode modified with quinone provides more methods and better options for the construction and development of asymmetric flexible micro-supercapacitors. (C) 2020 Elsevier Ltd. All rights reserved.