Balancing crystallinity and specific surface area of metal-organic framework derived nickel hydroxide for high-performance supercapacitor

Abstract Crystallinity and surface areas play important roles on the energy storage performances of electroactive materials. Herein, a Ni-based metal-organic framework ( MCF-35 ) is employed as the template to fabricate hierarchical Ni(OH) 2 for supercapacitor applications. By careful controlling of reaction time and pH of the reaction media, the crystallinity and surface areas of prepared Ni(OH) 2 could be tuned and an optimizing structure with balanced crystalline and surface area could be obtained. Such a structure offers high electrochemical active sites and efficient pathways for ion migration and electron transportation. Thus, a remarkable and excellent capacity of 250.6 mA h g −1 (2255 F g −1 ) at a current density of 0.5 A g −1 is achieved. Meanwhile, using active carbon and the optimized Ni(OH) 2 as electrodes, a hybrid supercapacitor is fabricated which exhibits an energy density of 42.54 Wh kg −1 at the power density of 370.8 W kg −1 .