Master’s thesis Nanotechnology: Preparation of manganese dioxide/graphene composites by plasma enhanced electrochemical exfoliation process and its electrochemical performance

Preparation Of Manganese Dioxide/Graphene Composites By Plasma-Enhanced Electrochemical Exfoliation Process And Its Electrochemical Performance

Author: Nguyen Thanh Hai

Field: Nanotechnology

Document Summary: This thesis presents a novel, straightforward, and environmentally friendly one-step method for synthesizing manganese dioxide/graphene composites with improved electrochemical performance. The composites were prepared using a plasma-assisted electrochemical exfoliation technique with a potassium permanganate precursor. Characterization was performed using SEM, TEM, XRD, Raman, and XPS, followed by an evaluation of their electrochemical behaviors. The synthesized MnO2/graphene composite demonstrated a specific capacitance of 217.0 F g⁻¹ at a current density of 2 A g⁻¹, significantly higher than pristine graphene (47.0 F g⁻¹). Notably, the capacitance retention exceeded 80% after 3000 cycles, attributed to the synergistic effect between MnO2 nanoparticles and graphene nanosheets. A symmetric supercapacitor fabricated from these composites achieved a highest specific capacitance of 130.9 F g⁻¹ at a current density of 2.5 A g⁻¹, highlighting this method as a promising approach for synthesizing MnO2/graphene composites for supercapacitor applications due to its efficiency, brevity, and eco-friendliness.

Detailed Table of Contents:

• TITLE PAGE
• TABLE OF CONTENTS
• LIST OF FIGURES
• LIST OF TABLES
• LIST OF ABBREVIATIONS
• ACKNOWLEDGMENTS
• DECLARATION
• ABSTRACT
• INTRODUCTION
• Chapter 1: OVERVIEW
  • 1.1. Electrochemical energy storages
  • 1.1.1. Supercapacitors
  • 1.2. Electrode materials for supercapacitors
  • 1.2.1. MnO2/graphene composites
  • 1.2.1.1. Direct oxidation-reduction reaction
  • 1.2.1.2. Solution-based mechanical mixing
  • 1.2.1.3. The other methods
  • 1.3. Current research in Vietnam
• Chapter 2: MATERIALS AND METHODS
  • 2.1. Chemicals and reagents
  • 2.2. Preparation of MnO2/graphene composites
  • 2.3. Preparation of graphene and GM1 electrodes
  • 2.4. Preparation of symmetric supercapacitor (GM1//GM1)
  • 2.5. Characterizations
  • 2.6. Electrochemical analysis
• Chapter 3: RESULTS AND DISCUSSION
  • 3.1. Characterizations of MnO2/graphene composites
  • 3.2. The proposed mechanism for PE3P method
  • 3.3. Electrochemical performance
  • 3.4. Symmetric supercapacitor
• CONCLUSIONS
• LIST OF PUBLICATIONS
• REFERENCES