SE990: Electrolyte design principles for alternative battery chemistries

Electrolytes are central to enabling alternative battery technologies that reduce reliance on lithium while meeting the performance, safety, and cost requirements of future energy-storage systems. This presentation examines how ionic conductivity, electrochemical stability, viscosity, solvation structure, interfacial compatibility, thermal stability, and mass transport govern device-level behavior. Understanding and balancing these properties is essential for designing electrolytes that support efficient ion transport while maintaining stable operation over repeated charge and discharge cycles.Electrolyte performance is governed by the coupled effects of salt selection, solvent or matrix composition, additives, and molecular interactions within the electrolyte. These variables control ion coordination, transport pathways, electrode/electrolyte interphase formation, and susceptibility to parasitic reactions. Connecting these fundamental properties to practical metrics such as rate capability, Coulombic efficiency, capacity retention, and temperature-dependent performance provides a basis for rational electrolyte design.Building on these general principles, this work highlights microemulsions and deep eutectic solvents as promising electrolyte platforms for alternative battery architectures. Microemulsions provide thermodynamically stable systems with nanoscale domains of immiscible liquid phases, offering control over ion-conducting pathways, local solvation environments, and interfacial behavior. Deep eutectic solvents offer a complementary approach through tunable composition, low volatility, and potentially favorable safety and sustainability characteristics. Together, these nontraditional electrolyte systems create opportunities to tailor transport, electrochemical stability, and electrode compatibility beyond the limits of conventional homogeneous electrolytes.