A Pseudo one dimensional model to describe the kinetic limitations in lithium–sulfur batteries

In the latest years Lithium sulfur batteries (Li S) have reached a wide interest in the research field as suitable candidate as post Lithium-ion batteries, due to their high theoretical specific capacity and potentially lower cost. However, their practical implementation is still hindered by several challenges principally related to the intrinsic chemistry of such system. Here is proposed a new modelling approach, a pseudo-one-dimensional (P1D) modelling framework is employed to investigate the role of polysulfides transport and precipitation kinetics as sources for reversible capacity losses, while guaranteeing low computational cost and avoiding mesh implementation. The model is parameterized on a CR2032 coin cell and validated against experimental discharge data over a broad current range, starting from 0.1C up to 1C. The model faithfully reproduces the characteristic two-plateau discharge profile and the supersaturation point associated with peak internal resistance. Providing a capacity reduction above 250[mAhg −1 ], primarily affecting the second voltage plateau, by increasing the current rate from 0.1C to 1C. Correlating the accumulation of intermediate polysulfides within the separator at high rates to reversible capacity losses, with concentrations up to five times higher compared to lower discharge rates. The framework discussed allows also to highlight the relationship between electrolyte viscosity, Li 2 S (s) precipitation kinetics, and internal resistance at different current intensity. Simulating an increase of the internal resistance of almost 50%, coupled also with a shift of the peak respect the state of discharge. The results proved the ability of the model to describe one of the major issues of lithium sulfur battery highlighting, at microscale level, its contribution on the precipitation kinetic, resistivity and its influence on the C-rate.