The Zhdanov model extends the Braginskii closure by considering arbitrary mixtures of ions with different mass and charge state. In particular, this results in transport coefficients for the electrons and different ion fluids that depend on the mixture, particularly for parallel dynamics.
There are additional ingredients for multi-ion simulations besides the Zhdanov closure. Firstly, the model requires reaction rates (chemistry) between the different ion species. Also reactions with different neutral gas species must be considered, requiring a more complex neutral gas model. Secondly, the code must allow the tracking of a variable number of species (ideally MPI parallelized), and consider their turbulence interaction via the polarisation drifts. Finally, one should consider that different boundary conditions could be required for the different species.