Electrochemical studies of solid solution electrodes

Abstract

Using a method based on the analysis of the voltage transient recorded during the application of a galvanostatic pulse to a solid state, three electrode cell, diffusion coefficients of silver electro-active species in AgₓTiS₁.₈ and AgₓNbS₂ were obtained. The activation energy of the diffusion process was found to be approximately 30 kJ mole⁻¹ for TiS₁.₈ and between 34 kJ mole⁻¹ and 24 kJ mole⁻¹, decreasing with increasing guest concentration, for NbS₂. Non-linearity at extended times in the experimental timescale was ascribed to finite length effects, variation of the thermodynamic enhancement factor during the pulse, or a combination of these influences.

Temperature and composition variation of the cell emf, for AgₓTiS₁.₈ and AgₓNbS₂ systems, permitted thermodynamic parameters and the compositional variation of the enhancement factors to be obtained.

Investigation of the effect of the temperature of oven pre-treatment on compressed powder samples of a lithium ion conducting vitreous electrolyte on the bulk conductivity was carried out using a scanning electron microscope and ac conductivity measurements.

Electronic conductivity measurements, using Wagner's method were undertaken on samples of iodotungstate and iodoarsenate glass with a view to confirmation of the low levels necessary for the use of these electrolytes in galvanic cells.