Corrosion of Lithium in Alkaline Solution

Abstract

The corrosion of Li was studied in 3-5M LiOH at 25~ and in 4.5M LiOH at 4~176 The Arrhenius relationship is obeyed and the apparent activation energy for the Li corrosion reaction is found to be 15.5 kcal mole -1. An em- pirical relationship is derived from which the corrosion rate vf can be obtained at any molar LiOH. At 25~ ,f(kA m -2) ---- 0.31(54.1 -- 10[LiOH] ). An equation is also given which allows calculation of the Li corrosion rate when the metal is anodically polarized. The kinetics of the He evolution reaction (e.r.) on Li were determined, the transfer coefficient ~ has a value of 0.14. The rate-con- trolling process of the Li dissolution reaction is the highly polarized I-I2 evolu- tion at cathodic sites. Based on the ~ value obtained, the enthalpy of activation for the He e.r. on Li at OCV is calculated to be 22.8 kcal mole -1. It is pro- posed that the protective film on Li has a duplex structure with a thin oxide/ hydroxide layer adjacent to the metal and an outer porous hydrated layer through which the reaction products and reactants can pass freely.