A global reliance on renewable energy sources necessarily requires the progression, and extensive adoption, of energy storage technologies in parallel. Among these, electrochemical energy storage is proving itself the most efficient means of banking energy for portable electronic devices, transportation, and grid-scale applications. Unfortunately, continued development of secondary batteries such as the lithium-ion battery have not kept pace with current energy demands. At present, much attention is directed towards deriving greater energy efficiency from lithium-based architectures while simultaneously moving towards advanced cell chemistries “beyond lithium-ion”. These research thrusts are heavily dependent on the development of novel cell components that can either directly improve battery performance, mediate lesser-developed electrochemical systems, or provide valuable insight into their complex, dynamic chemistry.Herein, the synthesis and implementation of novel electrolyte solutions are investigated for their influence in reversible electrochemical systems with the goal of advancing secondary battery technologies. The electrolytes studied here employ the exotic chemistry of carborane anions: weakly coordinating carbon and boron-containing cluster molecules renowned for their extreme thermal, chemical, and electrochemical stability. As a testament to these properties, presented are multiple systems in which carboranyl electrolytes are favorably paired with pure Li, Na, and Mg metal anodes. Central to this work is chemical modification of the anions which we explore in an effort to unlock favorable chemical and electrochemical properties in the resulting electrolytes. In one instance, we present a “sparingly solvated ionic liquid” species which is applied towards high capacity lithium-sulfur cell chemistries. In another, we expand the scope of carborane electrolytes to sodium metal anodes whose high reversibility is enabled by a fluorine-free solid-electrolyte interphase. Lastly, we incorporate similar anion functionalization strategies to achieve improved ionic conductivity and oxidative stability in an electrolyte applied to magnesium-ion batteries. Here, The carborane anion is demonstrated as an ideal platform for precision engineering strategies which represents a unique approach to electrolyte design.