Supercapacitor performance evaluation with changes of microstructure in carbon electrode from perylene diimide derivative

Abstract

Structural regulation of carbon electrode materials is an effective route to reinforce the performance of supercapacitors. Due to its high carbon content and easy gelation, perylene diimide derivative (PDI-d) is a good precursor for preparation of microstructure-controlled carbons. Here, PDI-d is synthesized and its gels are prepared under the action of glucono delta lactone (GDL). The PDI-d gels are subjected to freezing in liquid nitrogen or refrigerator, freeze-drying, carbonization for harvest of derived carbons with different structures and element doping. The derived carbons through liquid nitrogen freezing present fiber-woven three-dimensional connected porous structures, while those subjected to freezing in refrigerators are lamellar structures. N and Sn can be doped in the carbons using triethylamine (TEA) and K₂SnO₃·3H₂O as solvents for PDI-d dissolution, respectively. The carbons with connected pores show higher specific surface area (454 m² g⁻¹), and better electrochemical performance than the carbons with lamellar structures. The optimum specific capacitance (200.1 F g⁻¹) can be acquired in 3D porous carbons. The incorporation of N and Sn can further optimize the electrochemical performance. Specially, the Sn-doped porous structure derived carbon achieves a large energy density (27.79 Wh kg⁻¹) and keeps good cycle stability (94.7 % after 10,000 cycles).