- Title
- Development of electrochemical characterization methods and advanced capacitor materials
- Creator
- Forghani, Marveh
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- This thesis focuses on developing the most common electrochemical methods; cyclic voltammetry (CV) and step potential electrochemical spectroscopy (SPECS). Although CV and SPECS techniques have previously been used for characterising the performance of various energy storage devices, this study shows that there is always a room for improving the present electrochemical techniques and just repeating the conventional electrochemical methods is not the best approach to study the modern electrochemical storage devices with novel and more complex electrode materials. This thesis includes nine chapters. Chapter 1 is the introduction to the thesis. Chapters 2 to 4 focus on the literature reviews on the energy storage devices, electrochemical capacitor materials and electrochemical methods. Chapters 5 to 8 present four experimental studies on the electrochemical capacitors and Chapter 9 is the conclusion to this thesis. Herewith, the various experimental parameters involved in these two techniques have been further explored, and the performance of these methods for characterising the behaviour of electrochemical cells was compared experimentally. This thesis presents the application of CV and SPECS methods on testing electrochemical capacitors with various electrode materials such as activated carbon and manganese dioxide with aqueous and organic electrolytes. The SPECS method is based on applying a series of equal magnitude potential steps on a working electrode, with sufficient rest time to allow for quasi-equilibrium to be established for each step throughout an applied potential window. This slow sweep rate enables an electrode to approach its maximum charge storage capability. More importantly, it allows separation of charge storage mechanisms, such as electrical double layer charge storage and diffusion-limited processes. The effect of the two main experimental variables in SPECS; namely, the potential step size and the electrode rest time, on the behaviour of the electrochemical capacitor is described in Chapter 5. The contribution of the capacitive and diffusion-limited processes can be obtained via the voltammetric current-sweep rate dependence, voltammetric charge-sweep rate dependence and SPECS methods. These three methods were compared experimentally and also their limitations, and their advantages for interpreting the current data and their abilities to distinguish between the different charge storage mechanisms is presented in Chapter 6. Some of the complications associated with using a common approach; namely voltammetric current-sweep rate dependence, to deconvoluting double layer and diffusion-limited contributions to the performance of an electrochemical capacitor electrode, have been explored and presented in Chapter 7. Finally, Chapter 8 presents an improved methodology for the interpretation of SPECS data. The revised methodology provides an analysis method that produces performance data much closer to CV data, thus enabling both relative and absolute characterisation of electrochemical capacitor electrodes, as well as increasing the versatility of the SPECS analysis method.
- Subject
- electrochemical characterization methods; advanced capacitor materials; CV; SPECS; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1415683
- Identifier
- uon:36935
- Rights
- Copyright 2020 Marveh Forghani
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 6 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 222 KB | Adobe Acrobat PDF | View Details Download |