Anthraquinones-modified porous carbon as composite electrode for symmetric supercapacitor

The design of composited porous carbon-based electrode materials is keyed to improve the electrochemical performance for supercapacitors. Here, the natural carrot is used as a precursor to prepare porous carbon skeletons (CCs). Three different anthraquinones: anthraquinone (AQ), amino-anthraquinone (1-AAQ), and 2-aminoanthraquinone (2-AAQ) are used to modify the carbon skeletons with absorption. The maximum capacitance is obtained from material modified with 1-AAQ; it (1-AAQ-CC2) exhibits a noticeable pseudocapacitive performance with a brilliant capacitance of 328 F g −1 at 0.5 A g −1 and excellent cyclic stability (95% capacitance retention after 5000 cycles at 3 A g −1 ) in 2 mol L −1 KOH aqueous electrolyte. Moreover, the assembled 1-AAQ-CC2/1-AAQ-CC2 symmetric supercapacitor exhibits a high energy density of 14.8 Wh kg −1 at a power density of 240 W kg −1 operated at the voltage range of 0 to 1.8 V in 0.5 mol L −1 Na 2 SO 4 aqueous electrolyte. These results exhibit eco-friendly and low-cost design of organic and inorganic composite electrode materials for high-performance supercapacitors.