Rechargeable Mg batteries have been one of the most well-studied polyvalent-metal storage batteries owing to several merits, namely non-dendrite formation for Mg electro-deposition, high volumetric capacity and low cost. However, there are still a number of challenges for the development of Mg battery. For instance, lack of appropriate Mg electrolytes, defined as the “roadblocks” for Mg battery development. Before the successful invention of a prototype Mg ion battery, optimization of the Mg electrolyte performance and exploration of its compatibility with beyond Chevrel phase cathodes is necessary. Work presented here includes work for developing and characterizing non-halogen contained Mg electrolyte that can plate and strip Mg reversibly. Specifically, electrochemical evaluation of such new non-aqueous Mg electrolyte and its compatibility with beyond Chevrel cathodes will be discussed.