Vibrational Spectroscopic Studies of Electrode Surfaces and Technologically Important Electrolyte Solutions

Abstract : Laser Raman spectroscopy has been coupled with electrochemical techniques such as chronocoulometry and cyclic voltammetry to study the species adsorbed on electrode surfaces and to monitor processes which occur with changes in electrode potential, solvent properties, laser exciting line wavelength, solute and other variables. Lithium metal surfaces have been studied with the Raman microprobe; decomposition products, polymerization and conditions for this, and photo-currents were the subject of investigation. Work has been extended to the solvents methylacetate and propylene carbonate. Studies of selected aqueous electrolyte systems have been conducted for comparison. Chronocoulometry has been used to measure pyridine adsorption for single crystal and polycrystalline gold surfaces. In situ Raman spectra of smooth gold surfaces provided information about coverage in agreement with the isotherms from electrochemistry; the effect of surface roughness on the Raman intensity - potential profiles was measured. Studies of the identity and morphology of surface films that inhibit (or vice versa) the cycling efficiency of proposed lithium batteries have been studied; voltage-time transients from freshly cleaved lithium surfaces have been measured for a range of solvent-solute combinations.