Modeling the effect of electrolyte on the lithium sulfur battery performance

This thesis expands on this premise by presenting the impact of electrolyte amount and properties on the performance and lifespan of Li-S cells. To do so, the 0-dimensional electrochemical model by Marinescu et al. is implemented with a C-rate of 0.5 C. The 0-dimensional model is modified to predict continuous charge and discharge cycles and is simulated by using the Fortran programming language. To determine the effect of the amount of electrolyte on cell performance, the electrolyte-to-sulfur (E/S) ratio is altered by changing the electrolyte volume in the model directly. It is demonstrated that when the E/S ratio increases, the capacity of cell discharge remains unaffected, contrary to expectations. However, the capacity fading over the first two cycles is effectively predicted. The effect of electrolyte type and properties on cell performance is captured implicitly through model parameters and sensitivity analysis is conducted. It is shown that cell capacity is sensitive to changes in the initial voltage, the high voltage plateau standard potential, and the shuttle constant, whereas cell voltage output is sensitive to changes in E0, V , and high and low voltage plateau reaction exchange current densities. The model does not respond accurately to changes in the active area (ar), precipitation constant (kp), and C-rate. Furthermore, by adjusting the value of the shuttle constant (ks), the predicted cycling performance can align with experimental data for different E/S ratios and electrolyte types.