Synthesis of microsphere silicon carbide/nanoneedle manganese oxide composites and their electrochemical properties as supercapacitors

Synthesis of microsphere silicon carbide/nanoneedle MnO2 (SiC/N MnO2) composites for use as high-performance materials in supercapacitors is reported herein. The synthesis procedure involves the initial treatment of silicon carbide (SiC) with hydrogen peroxide to obtain oxygen-containing functional groups to provide anchoring sites for connection of SiC and the MnO2 nanoneedles (N-MnO2). MnO2 nanoneedles are subsequently formed on the SiC surface. The morphology and microstructure of the asprepared composites are characterized via X-ray diffractometry, field-emission scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The characterizations indicate that MnO2 nanoneedles are homogeneously formed on the SiC surface in the composite. The capacitive properties of the as-prepared SiC/N MnO2 electrodes are evaluated using cyclic voltammetry, galvanostatic charge/discharge testing, and electrochemical impedance spectroscopy in a three-electrode experimental setup using a 1-M Na2SO4 aqueous solution as the electrolyte. The SiC/N MnO2(5) electrode, for which the MnO2/SiC feed ratio is 5:1, displays a specific capacitance as high as 273.2 F g(-1) at 10 mV s(-1). (c) 2014 Elsevier B.V. All rights reserved.