Structural and Morphological Properties of MnO2/MWCNT Composite Grown Using the Hydrothermal Method for Supercapacitor Application

Abstract

Manganese dioxide and multi-walled carbon nanotubes (MWCNT) have received considerable recent interest for their potential application in supercapacitors, MnO2 as a pseudocapacitor material and MWCNT as an electrochemical double layer capacitance (EDLC) material. The combination of MnO2 and MWCNT is expected to make promising supercapacitor electrodes. In this study, MnO2 was mixed with MWCNT during the hydrothermal process. The difficulty in obtaining MnO2/MWCNT composite homogeneity in the hydrothermal process provides a challenge to scaling up production. KMnO4 and MWCNT were mixed with 20 mL distilled water and stirred using a magnetic stirrer for 2 minutes, then placed into an autoclave. Heating of autoclave was carried out at 160°C for 3 hours in an oven and followed by cooling at room temperature naturally. Manganese dioxide/MWCNT composites were made in 1:1 and 3:1 ratios. The diffraction peaks of composites indicated that incorporation of MWCNT into MnO2 has provided a crystalline orientation derived from MnO2 and MWCNT. Scanning electron microscopy and TEM imaging demonstrated that MnO2/MWCNT 3:1 composite attained better homogeneity than MnO2/MWCNT 1:1 as indicated by the attachment of MnO2 to the entire nanotubes surface of MWCNT. Increasing of conductivity values have been supported by MWCNT marked decreasing in the Rct value in electrochemical impedence spectroscopy measurements. Based on cyclic voltammogram measurements, the MnO2/MWCNT electrode 3:1 produced specific capacitation (Cs) of 252 F/g with stability up to 1000 cycles.

Unleashing the Potential: Augmented Supercapacitor Performance of Bi2O3/MnO2@MWCNT Nanocomposites with Redox Additive Electrolyte

“…Generally, reduced graphene oxide (rGO), graphene oxide, multiwalled carbon nanotubes (MWCNTs), and other carbon-based electrode materials provided excellent strength, conductivity, surface area, and moderate electrochemical properties. ,,, Moreover, the integration of MWCNTs in metal oxides/mixed metal oxides leads to enhanced electrochemical performances by the synergistic impact between the MWCNTs and metal oxides/mixed metal oxides. It originated from the amalgamation of the pseudocapacitive and electric double-layer capacitive (EDLC) behaviors of mixed metal oxides and carbonaceous materials, respectively.…”