Basic magnesium-doped nickel-based electrodes with card-on-lawn structure for supercapacitor with high energy density

Abstract

The rapid development of electrical energy storage (EES) technology is urgent for the exploitation of the supercapacitors with high energy density. The electrode plays a crucial role in the performance of supercapacitor. In this research, a basic magnesium-doped nickel-based (BMDNB) electrode material is successfully synthesized on a foamed nickel substrate by one-step hydrothermal method. After optimizing synthesis condition, the material has a unique card-on-lawn structure, nanocards are grown on a uniform honeycomb lawn array. The unique structure and compositions endow BMDNB prominent morphological features and excellent electrochemical properties. Using the BMDNB and active carbon as electrodes, an asymmetric supercapacitor (BMDNB//AC ASC) is assembled with a voltage window of 1.8 V. The ASC device achieves a maximum energy density of 74.9 Wh∙kg−1 at a power density of 1086.8 W∙kg−1. The energy density is comparable with the state-of-the-art level of the reported Ni(Mg)-based supercapacitors.