Greener, Safer, and Sustainable Batteries: An Insight into Aqueous Electrolytes for Sodium-Ion Batteries

Rechargeable Na-ion battery technology has successfully emerged as a replacement to the current Li-ion battery technology, especially in large-scale storage applications. Aqueous electrolytes in rechargeable Na-ion batteries have attracted extensive research due to its safety, low cost, and ecofriendliness, making a greener, safer, and sustainable solution for energy storage applications. One of the significant shortcomings for aqueous electrolytes for practical applications is the narrow electrochemical stability window (ESW) of the electrolyte and the chemical/structural stability of the electrodes in this ESW. This review focuses on and emphasizes the research developments using various electrolytic salts to maximize the voltage stability window and to arrest the loss of active materials in aqueous electrolytes.