Incorporation of α-MnO<sub>2</sub> Nanoflowers into Zinc-Terephthalate Metal–Organic Frameworks for High-Performance Asymmetric Supercapacitors
Balaji Chettiannan, Arun K. Srinivasan, Gowdhaman Arumugam, S. Shanavas, Mohammad Abu Haija, R. Ramesh
Abstract
High Resolution Image Download MS PowerPoint Slide Herein, we report the synthesis of α-MnO 2 nanoflower-incorporated zinc-terephthalate MOFs (MnO 2 @Zn-MOFs) via the conventional solution phase synthesis technique as an electrode material for supercapacitor applications. The material was characterized by powder-X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques. The prepared electrode material exhibited a specific capacitance of 880.58 F g –1 at 5 A g –1, which is higher than the pure Zn-BDC (610.83 F g –1 ) and pure α-MnO 2 (541.69 F g –1 ). Also, it showed a 94% capacitance retention of its initial value after 10,000 cycles at 10 A g –1 . The improved performance is attributed to the increased number of reactive sites and improved redox activity due to MnO 2 inclusion. Moreover, an asymmetric supercapacitor assembled using MnO 2 @Zn-MOF as the anode and carbon black as the cathode delivered a specific capacitance of 160 F g –1 at 3 A g –1 with a high energy density of 40.68 W h kg –1 at a power density of 20.24 kW kg –1 with an operating potential of 0–1.35 V. The ASC also exhibited a good cycle stability of 90% of its initial capacitance.