Electrochemical Behavior of Lithium in Alkaline Aqueous Electrolytes: III. Impedance Model

Abstract

An impedance model for the electrochemical dissolution of lithium in alkaline solutions is presented. The construction technique of the impedance function depends on calibration to steady-state properties, described in Part II of this series. The model, which is based on the point defect model for the growth and breakdown of passive films, is used to identify effects of various electrolyte solutes on the properties of the lithium film. The high frequency experimental impedance data are explained by the existence of a capacitance that is voltage and frequency dependent, a property that is theoretically rationalized. It is concluded that electrolyte solutes influence the rate of water transport through the outer layer, rate constants, the polarization of the barrier layer/outer layer interface, and the porosity of the outer layer. Based on the shape of predicted impedance signatures, it is suggested that the derived impedance equation may be applicable to other systems.

Effect of magnesium on the electrochemical behavior of lithium anode in LiOH aqueous solution used for lithium–water battery

“…11a). Cation vacancies are the predominant charge carriers in LiH film [23,24]. Consequently, the current efficiency is not markedly affected by magnesium addition (Fig.…”

“…The model and the interfacial reactions within the passive film on lithium are shown in Fig. 13 [10,23,24]. All the results above suggest that addition of magnesium to lithium changed the property of the bilayer film on the lithium surface.…”

“…The cathodic and anodic partial current densities were computed as −2FN H 2 and I T + 2FN H 2 . The coulombic efficiency of the system (Á) was calculated from the following equation [23,24],Á =…”

“…Interfacial reactions leading to generation and annihilation of point defects within the passive film on lithium[10,23,24].…”

Identification of reaction mechanism for anodic dissolution of metals using Electrochemical Impedance Spectroscopy

“…A mechanism that leads to features or patterns that are similar to the experimental data is chosen and the other mechanisms are rejected. The parameters can be estimated using optimization techniques [11,12] or by trial and error [10].…”