ABSTRACT
The supremacy of sodium and potassium over lithium is related to their electrochemical properties but to their critically higher abundance in the earth’s crust and, therefore, significantly easier availability and lower price. The driving force behind research on post-lithium multivalent materials is, therefore, related to surpassing the properties of these metals in terms of the achievable energy density. The gain of electrochemical properties like volumetric and gravimetric capacity, together with economical aspects, makes them much more attractive than the currently used Li-based materials. A high-dielectric-constant solvent may dissolve salts to sufficient concentration, but later, strong interactions between solvent molecules and ions will make them more resistant to electrochemical reactions. Additionally, the solvation shell can be much bigger than in the case of single-valence ions, decreasing ion mobility. The application of water-based electrolytes has many advantages, like low cost, simple operation, and favorable environmental factor.
