Utilization mild and green oxidation method to fabricate skin-core structure derived from non melting-shrinkage PPS carbon fibers with ultra-thin nanosheets for high performance asymmetric supercapacitor

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.