Assessing the feasibility of Na6MgCl8 as a material for all-solid-state sodium ion batteries: A theoretical approach

The search of outstanding materials used in sodium-ion batteries has to solve the two main challenges concerning the interfacial resistance between the solid-state electrolyte with the electrodes and relative high dc-conductivity at operative temperatures. In this work advanced atomistic simulations are used to evaluate the main properties of Na6MgCl8 rocksalt structure as a battery material for Na-ion Batteries. The results show that Na6MgCl8 has an insulating characteristic with an energy gap of -5.1 eV and is mechanically stable, ductile, and compatible with many possible electrodes/electrolytes. The simulations also predict that Zn2+ is the best divalent dopant, improving the defect characteristics and transport properties of Na6MgCl8. Large-scale molecular dynamics simulations show that Ba2+ and Zn2+ doping improve the Na ion transport, with a predicted Na conductivity of -10-7 Scm- 1 at room temperature. Overall, these results suggest that Na6MgCl8 can be considered as a promising material for use in Na-ion batteries and further experimental confirmation is needed to verify these predictions.