Three-dimensionally assembled manganese oxide ultrathin nanowires: Prospective electrode material for asymmetric supercapacitors

• Published in: Energy (Oxford) Vol. 188; p. 116066
• Main Authors: Ojha, Gunendra Prasad, Pant, Bishweshwar, Muthurasu, Alagan, Chae, Su-Hyeong, Park, Soo-Jin, Kim, Taewoo, Kim, Hak-Yong
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2019; Elsevier BV
• Subjects: 3D assembly; Asymmetry; Capacitance; Diameters; Electrochemical analysis; Electrochemistry; Electrode materials; Electrodes; Fabrication; Flux density; Graphene; Hydrogels; Life span; Manganese; Manganese dioxide; Manganese oxides; MnO2 nanowires; Nanotechnology; Nanowires; Oleylamine; Potassium; Potassium permanganate; Supercapacitor; Supercapacitors; X ray photoelectron spectroscopy; 3D assembly; Supercapacitor; MnO2 nanowires; Oleylamine
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2019.116066

In this report, we have forwarded a noble synthesis route for the fabrication of self-supported three-dimensional networks of manganese oxide ultrathin nanowires (3D MnO2-UTNWs) via a simple and cost-effective process for the first time. The formation of ultrathin nanowires (5 nm in diameter with several micrometer lengths) and their 3D assembly was achieved via a slow-reduction of potassium permanganate by oleylamine under constant stirring at 80 °C for 50 h. The resultant material was characterized using FE-SEM, TEM, XRD, FTIR, BET, XPS and Raman techniques. As-fabricated 3D MnO2-UTNWs network was used as the electrode material for supercapacitor. The electrochemical studies of the material revealed an excellent electrochemical performance with a high specific capacitance of 544.7 Fg-1 at 1 Ag-1 and excellent life span of 86.3% after 5000 cycles. An asymmetric supercapacitor was assembled using 3D-MnO2 UTNWs and nitrogen-doped graphene hydrogels (NGHs) as the positive and negative electrodes; respectively. The 3D-MnO2 UTNWs//NGHs device delivered an admirable specific capacitance of 56.5 Fg-1 at 1 Ag-1, energy density of 21 Whkg−1 at 840 Wkg-1, and extraordinary cyclic stability of 81.3% after 5000 cycles. This method provides a novel green synthetic route to prepare 3D MnO2-UTNWs without utilizing non-ambient reaction parameters. •3D-networks of MnO2 ultrathin nanowires were prepared.•The mechanism of 3D-network formation is discussed.•It showed high specific capacitance of 544.7 F/g at 1 A/g.•The nanowires were used as electrode material for asymmetric supercapacitor.•The synthesis process is simple, effective, and can be scaled up.