Effect of Bubbles and Liquid Drops Fluid Dynamics on the Lithium Recombination inside a Lithium Electrolytic Cell with Diaphragm

Abstract

Metallic lithium, which is a critical and strategic metal for the world’s production of energy storage devices, is mainly produced from molten salt electrolysis. To increase the efficiency of the process, it is of utmost importance to prevent lithium recombination during the process to avoid energy waste. This research studies the behavior of the main variables involved in the reaction inside a Li -production experimental cell from the mass transfer, electrochemical and fluid dynamics standpoints. Simulations were done for a total electrolysis time interval of 600 s using a turbulent (k- ε ) approach to solve the two-phase flow coupled to the lithium electrolysis process. To analyze the influence of cathode fluid dynamics in relation to the amount of recombined lithium, two configurations of the diaphragm were evaluated including the incorporation of a baffle at the bottom of the cell and the inclination of the diaphragm. The baffle reduced the amount of recombined lithium by 7 % , and the diaphragm with an inclination < 90° reduced the total recombined mass by 77 % , although it increased the energy consumption by 1 0 % with respect to the base case of a vertical diaphragm.