Surfactant‐Directed Engineering of Hierarchical Porous Heteroatom‐Doped Carbons for High‐Energy Supercapacitors

Abstract

Hierarchical porous heteroatom–doped carbons (HDCs) are readily fabricated through direct carbonization of polyimide precursors obtained in the presence of cetyltrimethylammonium bromide as a structure‐directing agent, showcasing tunable morphologies and porosities. The symmetric supercapacitor assembled by the optimized HDC electrodes with an aqueous electrolyte delivers a high specific capacitance (168 F g−1 at 0.5 A g−1), excellent rate capability (83.3% retention from 0.5 to 20 A g−1), and outstanding cycling stability (almost no capacitance fading after 10 000 cycles). Furthermore, the cell possesses a remarkable energy density of 8.4 Wh kg−1 at a power density of 150 W kg−1 and still maintains an energy density of 7 Wh kg−1 even at a high power density of 6000 W kg−1. Such exceptional supercapacitive performance shall be credited to the enlarged accessible surface area and pore volume for sufficient electrolyte contact and reservoir, chemically doped carbon skeleton for refined wettability, and high electronic conductivity as well as additional pseudocapacitive behavior. This work may open up a new possibility for fabricating low‐cost, lightweight, and durable supercapacitors with balanced energy and power delivery.