Anodic Behavior of Lithium in Aqueous Electrolytes: III . Influence of Flow Velocity, Contact Pressure, and Concentration

Abstract

The influence of electrolyte flow velocity, concentration, and contact pressure on the anodic behavior of lithium at constant temperatures in LiOH was studied. The experimental results reveal that, under constant load polariza- tion, a steady-state i-E curve is obtained consisting of resistance and con- centration polarization components. A method to accurately determine the film thickness was devised. It was found that the oxide film at the anode surface is quite thick, ca. 10 -2 cm, and its thickness remained constant irre- spective of polarization level at constant electrolyte concentration, flow rate, and anode-cathode contact pressure. The effective diffusion layer at the Li active surface is thin, ca. 10 -3 cm. The fraction of active surface area was found to change significantly with LiOH concentration (ranging from 0.05 in 4.84M to 0.39 in 2.9UM), but it was virtually independent of flow velocity and contact pressure. Likewise, electrolyte concentration has far greater in- fluence on film resistance than flow rate or contact pressure. Electrolyte flow velocity variation is, however, an effective means to alter power output from the cell.