To follow the displacements of all mobile species with respect to their original positions and to count the number of hops of each mobile ion, kMCpy uses a Tracker class in kmcpy.tracker. This class is activated only after the equilibration is complete. The Tracker is initialized with the initial occupation vectors, a reference crystal structure of the simulation cell, the formal charge on migrating species, the dimensionality of the overall diffusion process, the average hopping distances (in Å), the simulation temperature, and ν * . The initial location of each migrating species is recorded and their Using Eqs. 2-7 in Sec. II, Tracker computes transport properties, such as MSD, D J , D * , σ , f , and H R from the displacements of all migrating ions. The chemical diffusivity, D c (Eq. 2) can be computed once Θ is identified for systems with variable compositions, such as electrodes . Tracker.summary() and Tracker.write_results() routines print and save the simulation results, respectively.