Synthesis of Boron and Nitrogen Codoped Porous Carbon Foam for High Performance Supercapacitors

A facile and efficient method to prepare boron and nitrogen codoped porous carbon foam (BNPC) derived from starch with urea as nitrogen source and boric acid as both boron source and templet is presented. The codoping strategy can boost the synergistically doping amounts of boron and nitrogen, which can achieve a great increase in the doping efficiency of boron (three times higher than single boron doping) and nitrogen. Due to its hierarchical pore structure with moderate specific surface and relatively high nitrogen (9.38 at. %) and boron (3.87 at. %), the BNPC electrode exhibits outstanding electrochemical performances with an ultrahigh specific capacity of 402 F g–1 at a current density of 0.5 A g–1 and retains 266 F g–1 even at a current density of 20 A g–1 in 6 M KOH electrolyte. In addition, a symmetric device based on BNPC electrodes delivers a respectable energy density of 21.9 Wh kg–1 in 1 M Na2SO4 electrolyte. Therefore, this work provides a simple and efficient method to synthesize heteroatom-doped hierarchical porous carbon materials for advanced energy storage systems.