ZnO@MnO2 Core–Shell Nanofiber Cathodes for High Performance Asymmetric Supercapacitors
- 25 October 2016
- journal article
- research article
- Published by American Chemical Society (ACS) in ACS Applied Materials & Interfaces
- Vol. 8 (44), 30531-30542
- https://doi.org/10.1021/acsami.6b08082
Abstract
Asymmetric supercapacitors (ASCs) with aqueous electrolyte medium have recently become the focus of increasing research. For high performance ASCs, selection of cathode materials play a crucial role and core-shell nanostructures are found to be of a good choice. We successfully synthesised, ZnO@MnO2 core-shell nanofibers (NFs) by modification of high-aspect-ratio-electrospun ZnO NFs hydrothermally with MnO2 nanoflakes. High conductivity of the ZnO NFs and the exceptionally high pseudocapacitive nature of MnO2 nanoflakes coating delivered a specific capacitance of 907 Fg-1 at 0.6 Ag-1 for the core-shell NFs. A simple and cost-effective ASC construction was demonstrated with ZnO@MnO2 NFs as a battery-type cathode material and a commercial-quality activated carbon as a capacitor-type anode material. The fabricated device functioned very well in a voltage window of 0 - 2.0 V and a red-LED was illuminated using a single-celled fabricated ASC device. It was found to deliver a maximum energy density of 17 Whkg-1 and a power density of 6.5 kWkg-1 with capacitance retention of 94% and coulombic efficiency of 100%. The novel architecture of the ZnO@MnO2 core-shell nanofibrous material implies the importance of using simple design of fiber based electrode material by mere changes of core and shell counterparts.Keywords
Funding Information
- Department of Science and Technology, Ministry of Science and Technology (SR/NM/NAT/02-2005)
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