GITT Evaluation with PyBaMM

The accuracy of the galvanostatic intermittent titration technique (GITT) for determining solidstate lithium diffusion coefficients was systematically evaluated using synthetic data generated with Doyle–Fuller–Newman model in PyBaMM. GITT-derived diffusion coefficients were compared with the known values used to generate the data across a broad range of possible material properties. GITT systematically underestimated the diffusion coefficient, with absolute errors increasing at higher diffusivities. For an optimized cell, reliable determination was generally limited to D ≤ 10 -14 m2/s, while a non-optimized cell provided much worse performance. These results demonstrate that GITT-derived diffusivities should be used with caution for quantitative battery-model parametrization. Nevertheless, GITT remains useful for comparative materials evaluation when cell design and analysis conditions are kept consistent.