(Invited) Achieving Stable Interfacial Reactions in Sodium Batteries through Electrolyte Engineering

Abstract

Cost and lithium supply issues supply are compelling reasons to consider sodium batteries as potential alternatives to the better-known lithium-ion analogs for large-scale applications, including vehicles. Sodium-ion batteries have been the most highly developed system, with some commercialized systems demonstrate practical energy levels exceeding those of Li-ion batteries with LiFePO4. Further improvement in energy densities requires the development of new high-performance electrode materials (cathode/anode) and compatible electrolytes to achieve milestones in cycle life. In this work, we report the electrolyte engineering basically focusing on the electrolyte formulation (salt/additive selection), solvation structure of the electrolyte, and tuning on SEI/CEI composition. Our strategies thus enable high energy density of Na-metal and Na-ion batteries with remarkable cycle life. The presented insights differ from a prevailing stabilizing interfacial reaction that can be achieved by tuning SEI/CEI composition and providing a guiding principle in electrolyte design for sodium batteries.