Zn-ethylenediaminetetraacetic acid complex derived N-doped porous carbon for high-performance supercapacitor

The development of N-doped porous carbon is an effective strategy to improve supercapacitor performance such as energy density and rate capability. The synthesis of N-doped porous carbon with high surface area by a simple method remains a challenge since it usually requires an additional chemical activation. In this work, we developed Zn-ethylenediaminetetraacetic acid (EDTA) coordination complexes, and then synthesized N-doped porous carbon with high surface area through pyrolysis of Zn-EDTA complexes based on the high nitrogen content of EDTA and the activation ability of Zn species. The morphology and surface area of the obtained porous carbon significantly depend on the morphology of the Zn-EDTA complexes, which can be easily controlled by adjusting the amount of Zn salt. The porous carbon exhibited a specific capacitance of 251.9 F g−1 at 1 A g−1 and 194.4 F g−1 at 20 A g−1 in a two-electrode system. Furthermore, the assembled supercapacitor device displayed an energy density of 8.7 Wh kg−1 at a power density of 248.7 W kg−1 at 1 A g−1 and good cycling performance with capacitance retention of 100 % over 10,000 cycles at the current density of 10 A g−1. The excellent supercapacitive performance should be mainly ascribed to the large surface area and abundant micro-, meso-, and macropores, which offer large electrode/electrolyte interfaces and fast ion diffusion. In addition, the high-level and uniformly distributed N atoms endow the porous carbon with both a high concentration of active sites and good wettability.