Quantitative Galvanostatic Intermittent Titration Technique for the Analysis of a Model System with Applications in Lithium-Sulfur Batteries

The galvanostatic intermittent titration technique (GITT) is a powerful characterization tool for batteries, which provides key thermodynamic and kinetic information about battery performance. However, the quantitative analysis of GITT measurements for lithium-sulfur batteries has so far been limited to the evaluation of the internal resistance of the cell and the equilibrium voltage profiles. In this work, we provide the mathematical framework to characterize the mass-transport kinetics in lithium-sulfur batteries from GITT data, and we demonstrate the validity of the approach through the application to a model and well-behaved system, ethyl viologen, whose diffusion coefficient is corroborated by cyclic voltammetry data. The present approach is also advantageous for the analysis of ion-insertion electrodes, where non-linearity of concentration and voltage changes would produce unrealistic evaluations of the diffusion coefficient by the classical analysis of GITT data.