Edge-N-Dominated Nanoporous Carbon as Electrode Materials for Enhanced Performance in Aqueous Supercapacitors
Ping Yuan, Xianyou Luo, Shengwei Li, Haoming Xiao, Junyi Li, Junhui Luo, Yong Chen, Daming Chen, De Li
Abstract
N-doped nanoporous carbon (NPC) has widely been used as electrode materials for supercapacitors owing to its high specific capacitance, superior rate capability, and long-life cycling performance. However, exploring the charge distribution mechanism of NPC with various types of N species under different charged states remains challenging. Herein, NPC derived from petroleum coke was prepared by the KOH activation method. The electrochemical testing suggested satisfactory capacitance performance of the as-obtained edge-N-dominated nanoporous carbon. An assembled symmetric supercapacitor device in a 6 M KOH electrolyte delivered a specific capacitance reaching 220 F g –1 at a current density of 1 A g –1, a value 37.5% higher than that obtained by pristine carbon (160 F g –1 ). The theoretical calculation results demonstrated a high adsorption capacity of edge-N toward K + . The increase in net charge on the electrode materials led to the accumulation of electrons on N-dopants, forming a negative charge center relevant to strengthening K + adsorption. Overall, insights into the effect of N species on charge distribution in different charged states were provided, conducive to guiding the large-scale development of supercapacitors and other energy storage devices.