Low cost, abundance in the crust of the earth, and free dendritic growth are the attractions of magnesium metal to be the alternative in the near future to lithium metal anodes in rechargeable battery applications. However, the development of magnesium batteries faces several challenges, most notably the lack of a thermodynamically stable electrolyte at a low potential and the development of a suitable functional cathode to accommodate the bivalent Mg2+ ions with a reasonable capacity. There have been achievements made after the discovery of the Mo6SChevrel-phase cathode and the family of Mg organohaloaluminate electrolytes, and there is ongoing work to create and engineer new energetic materials that can overcome the obstacles that hinder realizing a practical Mg battery. This chapter focuses on recent research in developing materials and insights for magnesium battery applications. Three major aspects to be covered are: (1) electrolyte design and synthesis; (2) development of intercalation-type cathodes; and (3) understanding of the mechanisms of Mg intercalation or chemical interaction of the electrolyte with the electrodes. The main goal is to gain current insights that can help in making significant inroads that could eventually lead to a high-performance Mg battery.