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Two crucial elements that aid in the development of supercapacitors are the usage of distinctive components and the creation of optimal structures. In view of this, polyphenylene sulfide (PPS) non-woven fibers prepared by melt-blast process are used as carbon precursor, and oxidized polyphenylene sulfide (O-PPS) was prepared by an innovative and environmentally friendly oxidation method, which overcame the melting and shrinkage of PPS at high temperatures. After carbonization, flexible carbon fibers (SCFs) with high specific surface area were formed by O-PPS. Then, polypyrrole (PPy) and metal-organic framework material (Co-MOF) are successively grown on the SCFs, and the Co-MOF is transformed into layered double hydroxide (NiCo-LDH) ultra-thin nanosheets (ca. 4 nm) with rich electrochemical active sites under nickel nitrate etching, which obtains the "skin-core" structure composite electrode. This materials' high specific capacitance of 1705.6 F g−1 at 1 A g−1, and the electrode reaction process is governed by the pseudocapacitance characteristic. Asymmetric supercapacitors assembled with porous carbon possesses 46.96 Wh kg−1 at 725 W kg−1, and the capacitance retention rate is 81.47% after 8500 cycles. This research provides a new combination of ultra-thin NiCo-LDH nanosheets with carbon fiber for energy storage while improving the energy density of supercapacitors. [Display omitted] • A greener and milder polymer oxidation process. • This material owns "skin-core" structure with ultra-thin nanosheet loaded. • The assembled asymmetric supercapacitor exhibits superior capacitance behavior. [ABSTRACT FROM AUTHOR]

As a kind of cheap and easily available organic molecular with Faradic redox activity, quinones can well combined with carbon-materials by non-covalent π–π conjugation and remedy its shortcomings possessing relatively low specific capacitance. However, in previous studies, the combination of quinones and carbon-based materials often requires toxic organic solvent or high energy-consuming and interminable process, greatly hindering their practical application. Here we use water-soluble sodium anthraquinone-2-sulfonate (AQS) and graphene oxide (GO) solution as raw materials to directly obtain AQS composite reduced GO (AQS/rGO) hydrogels by chemical reduction, the whole process of which is performed at relatively low temperature and normal pressure, and only takes a short time, resulting in great promotion in sustainability and efficiency. The AQS/rGO hydrogel exhibiting a high specific capacitance of 387.43 F g−1 at 1 A g−1 and an excellent cycling stability of 91.11% after 10000 cycles at 10 A g−1, has a prodigious improvement for the pure graphene in all aspects. Besides, the maximum energy density of the asymmetric supercapacitor assembled by AQS/rGO-1 hydrogel reaches 15.98 W h kg−1 at the power density of 325.02 W kg−1. This work provide a new idea for the green and efficient preparation of graphene organic quinones composite and has an important significance for its practical application. • AQS can be combined with graphene sheet by non-covalent π-π conjugation. • The process of preparing AQS/rGO hydrogels is utrla-simple, green and efficient. • The AQS/rGO hydrogels exhibits superior electrochemical performance to pure graphene. • The asymmetric supercapacitor delivers high energy density. [ABSTRACT FROM AUTHOR]