Electrodeposition of alkali group I metals from room temperature ionic liquids
<p>The work presented in this thesis involves the utility of room temperature ionic liquids (RTILs) as solvents in electrodeposition of Alkali Group I metals (excluding Fr). The first two chapters present fundamentals of electrochemistry which is the basis of this work followed by an overview...
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2011
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| Summary: | <p>The work presented in this thesis involves the utility of room temperature ionic liquids (RTILs) as solvents in electrodeposition of Alkali Group I metals (excluding Fr). The first two chapters present fundamentals of electrochemistry which is the basis of this work followed by an overview of RTILs and a brief introduction to X-ray photoelectron spectroscopy. The results of five original studies are then presented as follows:</p> <p>• The deposition and stripping of Li/Li<sup>+</sup> couple in several RTILs is studied in detail on Pt and Ni microelectrodes and the results are simulated using a mathematical model developed by the Compton Group</p> <p>• The study is then continued for Na/Na<sup>+</sup> in several ionic liquids on a Ni microelectrode and the results are compared to that of Li/Li+ couple</p> <p>• The remaining members down the Group (K/K<sup>+</sup>, Rb/Rb<sup>+</sup> and Cs/Cs<sup>+</sup>) are studied in ionic liquid N-butyl-N-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide ([C<sub>4</sub>mpyrr][NTf<sub>2</sub>]) on a Ni microelectrode allowing comparison of electrode potentials throughout Group in the IL to be deduced.</p> <p>• The novel development of <em>in situ</em> electrochemical-X-ray photoelectron spectroscopy for monitoring the potassium deposition is reported</p> <p>• Electrochemical-XPS is used for monitoring rubidium deposition in competition with RTIL solvent breakdown</p> <p>The results presented show that several RTILs are able to support the electrodeposition of Alkali Group I metals due to their wide electrochemical windows and electrochemical stability. The simulation of the results allows thermodynamic and kinetic parameters such as the electrochemical rate constant (<em>k<sup>0</sup></em>), diffusion coefficient (<em>D</em>), and formal potential (<em>E<sub>f</sub><sup>0</sup></em>) and transfer coefficient (α) to be extracted. The trend in electrode potentials of the Group in [C<sub>4</sub>mpyrr][NTf<sub>2</sub>] is also presented and compared to that of in other solvents. The near zero vapour pressure property of the RTILs is also exploited for the development of <em>in situ</em> electrochemical-XPS; a new branch of spectroelectrochemistry.</p> |
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