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Fabrication and Characterization of Electrochemical Properties of Porous Ni and Ni/rGO Nanocomposite by Electrochemical Deposition for Pseudocapacitor Application

Sabzeh, Parisa | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55415 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Abachi, Parvin; Dolati, Abolghasem
  7. Abstract:
  8. Fabrication of porous hybrid coatings, specially in combination with carbon compounds, can improve the electrochemical behavior of the coating. In this study, graphene oxide (GO) was first synthesized by tour method. After examining different methods to create a porous coating, the electrochemical coating method for simultaneous deposition of GO and nickel on the copper substrate was selected. CTAB was used to form nanometer porosity in the coating structure. In order to investigate the effect of GO on the properties of the deposited coating, two porous coatings of nickel (Ni) and nickel reduced-graphene oxide (Ni-rGO) were investigated by different analyzes. These analyzes include FESEM analysis to investigate the microstructure of the coating, XRD and raman analysis to investigate the chemical composition and identification of crystalline phases, FTIR analysis to investigate the compounds and bonds formed between the components, and electrochemical cyclic voltammetry (CV) to investigate the specific surface area and charge stored in the coating and the electrochemical impedance spectroscopy methode (EIS) were used to investigate the electrical conductivity of the coating. The results showed that GO sediments were evenly distributed in the porosity of the nickel coating. Comparison of FESEM images also showed that the shape and size of pores were similar and uniform in both Ni and Ni-rGO coatings. According to the results of electrochemical tests, porous nickel-rGO coating has a higher capacity to store electric charge than porous nickel coating, and also has a higher specific surface area, which helps to increase electric charge capacity. The specific surface area of Ni-rGO and Ni coatings was 501 cm2 and 312 cm2, respectively, indicating that, the presence of two-dimensional rGO plates increase the specific surface area of the coating, which causes the specific capacitance of the coating containing rGO reach to 1127 Fg-1 while the specific capacitance of the Ni coating was aroun 803 Fg-1. Also the electrical conductivity of the coating in the presence of the rGO reached to 0.4 S, while the electrical conductivity of the Ni coating was 0.11 S, which proves that the presence of rGO plates increased the conductivity. Therefore increasing the capacity and conductivity of the porous nickel coating surface by rGO layers makes it possible to achieve higher capacities charge accumulation in the coating.
  9. Keywords:
  10. Transition Metal Hydroxide ; Reduced Graphene Oxide ; Hybrid Porous Coating ; Porous Coating ; Pseudocapacitance Property ; Electrochemical Properties ; Electrochemical Deposition

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