A comprehensive review of lithium salts and beyond for rechargeable batteries: Progress and perspectives

The increasing need for energy storage has been the motivation for intensive research in batteries with different chemistries in the recent past. Among the elements of the batteries, the salts and their solvent play an important role. In particular, the cathodic stability at low potential depends importantly on the choice of the cation, while the stability at high potentials is mainly due to oxidation of anions and the ion mobility and dissociation depend primarily on the delocalization of the anion, so that many attempts are made to find the optimum choice of both the cations and anions of the salts, and their solvents. Although lithium-based batteries are almost exclusively used today, efforts are currently made to explore batteries based on sodium, aluminum, magnesium, calcium, potassium. The purpose of the present work is to review the salts and solvents that have been proposed in these different batteries and discuss their properties and their ability to be used in the near future and in the next generation of batteries.