The lithium sulfur battery is a promising energy storage device due to its high theoretical energy density and the abundancy of sulfur deposits. One of the key issues that limits this chemistry is the precipitation of Li₂S in the discharge process. Because of its low solubility in the electrolyte solution, Li₂S deposition on the surface impedes the reaction by increasing the impedance at the interface. In this study, we will describe a mathematical model, based on the phase field approach, to track the precipitation of Li₂S during the discharge process. The phase field model is employed because of the ease of modeling the interfacial region, by employing continuous order parameters between two adjacent phases to avoid tracking the sharp interface. The influence of different operating parameters will be explored to reveal the mechanisms behind the precipitation process.