Scalable in-situ growth of self-assembled coordination supramolecular network arrays: A novel high-performance energy storage material

Abstract

The exploration and rational design of new micro/nanostructured electrode materials with high capacitance performance is highly desired for supercapacitors. In this study, a novel coordination supramolecular network (CSN) of [Ni(Hsal)2(H2O)4] (Ni-Hsal, where Hsal is salicylate) sub-micrometer rod arrays has been synthesized directly on nickel foam by a facile solvothermal method. The nickel foam functionalized as both nickel ions source and current collector. The electrochemical tests demonstrate that this Ni-Hsal electrode has high areal capacitance of 6.04 F cm−2 at a current density of 10 mA cm−2, good rate capability with 76.2% capacitance retention when the current density increased from 10 mA cm−2 to 50 mA cm−2, and excellent cycling stability (showing no performance degradation after cycling 6000 times at 80 mV s−1). Furthermore, an asymmetrical supercapacitor (ASC) using the Ni-Hsal cathode and activated carbon (AC) anode is fabricated, which achieves an energy density of 2.39 mW h cm−3 and a maximum power density of 1.82 W cm−3 as well as excellent stability with a capacitance retention of 94% after 15,000 cycles. These results demonstrate that the CSNs can be a competitive electrode materials for supercapacitors in energy storages.