Academic department under which the project should be listed

CSM - Chemistry and Biochemistry

Faculty Sponsor Name

Altug Poyraz

Abstract (300 words maximum)

Nanostructured manganese dioxides are attractive cathode materials in aqueous supercapacitors due to their low cost, environmental benign nature, high theoretical gravimetric capacitance, and power in neutral aqueous electrolytes. In this work, a layered birnessite-type manganese dioxide (δ-MnO2) is synthesized utilizing solid-state redox method with superoxide. The effects of temperature and oxidant amount on the physicochemical properties of δ-MnO2 are characterized using Elemental Dispersion X-ray (EDX) spectroscopy, X-ray diffraction (XRD), N2-sorption, and Scanning Electron Microscope (SEM). The physiochemical properties that are specifically analyzed by varying synthesis conditions pertain to the chemical composition, morphology, and surface area of various δ-MnO2 materials. Through EDX spectroscopy, a link between potassium content and temperature is found with potassium content in the material rising to a maximum of 10.24% with the synthesis temperature at 160°C. The electrochemical performance of δ-MnO2 was evaluated utilizing 3-electrode beaker cells with 1.0 M Na2SO4 as the aqueous electrolyte. The 3-electrode beaker cell consisted of a stainless-steel gauze working electrode, a graphite counter electrode, and an Ag/AgCl reference electrode. Electrochemical tests (cyclic voltammetry) were performed with the synthesized variants of δ-MnO2 and demonstrated high capacitance with values such as 162 F/g at a scan rate of 2mV/s and 106.5 F/g at a scan rate of 20 mV/s.

Project Type

Poster

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Solid-state Redox Synthesis of Layered birnessite-type Manganese Dioxide (δ-MnO2) as Aqueous Supercapacitor Electrodes

Nanostructured manganese dioxides are attractive cathode materials in aqueous supercapacitors due to their low cost, environmental benign nature, high theoretical gravimetric capacitance, and power in neutral aqueous electrolytes. In this work, a layered birnessite-type manganese dioxide (δ-MnO2) is synthesized utilizing solid-state redox method with superoxide. The effects of temperature and oxidant amount on the physicochemical properties of δ-MnO2 are characterized using Elemental Dispersion X-ray (EDX) spectroscopy, X-ray diffraction (XRD), N2-sorption, and Scanning Electron Microscope (SEM). The physiochemical properties that are specifically analyzed by varying synthesis conditions pertain to the chemical composition, morphology, and surface area of various δ-MnO2 materials. Through EDX spectroscopy, a link between potassium content and temperature is found with potassium content in the material rising to a maximum of 10.24% with the synthesis temperature at 160°C. The electrochemical performance of δ-MnO2 was evaluated utilizing 3-electrode beaker cells with 1.0 M Na2SO4 as the aqueous electrolyte. The 3-electrode beaker cell consisted of a stainless-steel gauze working electrode, a graphite counter electrode, and an Ag/AgCl reference electrode. Electrochemical tests (cyclic voltammetry) were performed with the synthesized variants of δ-MnO2 and demonstrated high capacitance with values such as 162 F/g at a scan rate of 2mV/s and 106.5 F/g at a scan rate of 20 mV/s.