The Diffusion of Lithium in Lithium-Zinc Alloy

Abstract

In a new type of secondary battery with a Li-Zn alloy as one electrode, chlorine as the other and a molten salt solution of LiCl-KCl, polarizations during charge and discharge at the Li-Zn alloy electrode may occur due to the slow diffusion of Li companying K in the alloy. This was examined by the use of chronoamperometric and chronopotentiometric methods. With a cathodic charge, the apparent diffusion coefficient of Li companying K was about 3.5×lO⁻⁵ cm²/sec at 500°C, whereas that of Li alone was about 6.0×l0⁻⁵ cm²/sec. Underan anodic discharge, the apparent diffusion coefficient was extremely large (the order of 10⁻⁴ cm²/sec), and this may be caused by the existence of convection at the alloy-electrolyte interface. The optimum charging and discharging current densities of the battery were estimated to be 0.2 and 0.3 A/cm² respectively.