ABSTRACT
Rechargeable batteries are still in their infancy meeting the requirements of energy storage applications such as electric vehicles, portable energy storage devices, etc. [1, 2]. A need for sustainable and economically viable energy storage devices is crucial. Currently, lithium-ion batteries rule the electrochemical world, but they are handicapped by their risk of hazards and cost [3]. Magnesium-ion batteries are an alternative system for lithium-ion batteries and are superior in terms of safety. Redox potential of magnesium (Mg) is -2.38 V [4], which is greater than lithium (-3.04 V), paving the way for an easy charge—discharge process. The charging process of batteries leads to the intercalation of ions (Li+/Mg2+) in the cathodes; the volume of occupancy for two lithium (Lit) ions is higher than that of a single Mg2+ ion [4, 5]. Therefore, because of the bivalency of Mg ions, more charge can be stored in a minimum volume, which is an added advantage for miniaturization of energy storage devices. During lithiation process, volume expansion occurs, and, as a result, structural deformation takes place in the process of delithation at the cathode, decreasing the electric contact and cyclability [6-8]. Alkali metals in anodes are not safe because they are reactive and have the potential for dendrite formation. Mg metals are compatible with anodes and are safe; a schematic diagram of Mg-ion battery is shown in Figure 8.1. Research on Mg-ion batteries has impelled its importance in many industries and academic institutions. Advanced Project Research Agency, Pellion Technologies, and Toyota Research Institute in North America initiated the development of Mg-ion batteries. Pellion Technologies focused mainly on the core issue related to Mg-ion deposition/dissolution and found an alternative method to tackle problems [8, 9]. At the same time, Toyota Research Institute’s research focused mainly on developing high-energy, high-density Mg-sulfur (Mg-S) batteries.
