NaSICons (Na Super Ionic Conductors, discovered by Hong and Goodenough 1975) are a very useful   family of solid electrolytes with potential technological applications in high energy density batteries, fuels cells, etc. The prototypical NaZr2P3O12 consists of a rigid oxide framework of corner shared ZrO6 octahedra and PO4 tetrahedra. The large number of alkali ion sites that populate the framework in high density are well connected by channels of low energy barriers allowing fastion transport. The NASICON structure permits a wide range of ion substitution at the Zr and P sites making them a versatile family of solids. Among other useful properties of these materials are the high thermal and chemical stability, and low/negative thermal expansivities.               
Our studies on these solids began with the development of a high quality inter-atomic potential that reproduces several known experimental data in excellent agreement. Faithful reproduction of the structural parameters and ionic conductivity as functions of both temperature and alkali ion content, and the site occupancy of alkali ions are particularly note worthy. The simulation studies employing the model provides valuable atomic level picture of a variety of phenomena, such as, the nature of the fast ion transport, phase transitions and low thermal expansivity of these solids. The study also resolved some of the long debated issues related to the preferred conduction channel in these solids. The enhanced diffusion of optimally-sized ions in NASICON framework predicted in our study forms a very useful insight in the tailor making of superionic solids. 

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