N, S Codoping and Mesoporous‐Induced Capacitive Storage Enhancement in Supercapacitor and Improved Li–S Battery Performances of Polystyrene Waste‐Derived Carbon Electrode

Abstract

The accumulation of solid polymer wastes stifles society's sustainable growth. Herein, N‐, S‐codoped polystyrene (thermocol) waste‐derived carbon is synthesized using a simple approach and utilized as an electrode for a lithium–sulfur battery and supercapacitor applications. The aqueous symmetric supercapacitor delivers a high specific energy of 60 and 27 Wh kg−1 at a specific power of 75 and 3780 W kg−1, respectively and 150 Wh kg−1 at a specific power of 520 W kg−1 in nonaqueous sodium‐ion capacitors with high cycling stability. Deconvolution by Dunn's and Trasatti's approaches reveals an enhanced capacitive‐charge storage rather than diffusive‐charge storage due to heteroatom doping and mesopores of the generated carbon. The lithium–sulfur battery delivers a stable capacity of 1079 mAh g−1 at 0.1C rate with excellent cycling stability over 500 cycles, suggesting improved mitigation of polysulfide dissolution imparted by the mesoporous carbon with thiophene moiety which effectively traps Li2S n .