Preparation of nickel-bound porous carbon and its application in supercapacitors

Abstract

In this study, nickel-bound porous carbon (Ni-PC) was prepared by introducing Ni²⁺ into dipotassium ethylenediaminetetraacetate (EDTA-2K) derived nitrogen-doped porous carbon (PC) using the ball milling method. This solvent-free mechanochemical method is eco-friendly and rapid, because reactions are triggered by mechanical forces under extremely high concentrations of reactants. PC possesses a large specific surface area and abundant N/O-containing groups, which can coordinate with Ni²⁺, leading to excellent atomic dispersion and use in faradaic reactions. Therefore, Ni-PC exhibited high stability and excellent pseudocapacitance performance as a supercapacitor electrode material. Ni-doped PC was also prepared using pyrolysis and solution methods for comparison. The sample prepared by the ball milling method exhibited the best performance, a large specific capacitance (565 F g⁻¹, 1 A g⁻¹), a high-rate capability (358 F g⁻¹, 10 A g⁻¹), and superior cycling stability (105.8% capability retention after 10 000 cycles at 10 A g⁻¹). Moreover, the asymmetric supercapacitor device Ni-PC//AC (AC, activated carbon) exhibited excellent application prospects. This study provided a novel method for preparing metal-ion-bound PC and verified its use in energy storage devices.