Electrode impedances in fused alkali nitrates

Abstract

The impedance method has been used to study electrode processes in the molten ternary eutectic of LiNO₃+ NaNO₃+ KNO₃ at ∼140°C. A dropping mercury electrode was used in conjunction with a synchronized impedance bridge. The concentration-, potential- and frequency-dependence of the impedances of systems containing chloride, bromide, nickel, lead, cadmium, thallium and zinc ions was examined. In each case it was possible to separate the double-layer capacity, the Warburg impedance and, in two cases, the charge-transfer resistance. The results confirm the importance of considering spherical diffusion and also the superiority of the semi-infinite diffusion theory over that of the steady state.