Frontier Electrolytes for Efficient Sodium-Ion Batteries

The considerable demand for renewable energy sources and the mounting concern about environmental pollution has created a new development opportunity in the field of secondary batteries, which can store chemical energy in place of electrical energy. In the 2010s, attention was drawn to sodium batteries. A sodium-ion battery (SIB) is a specific kind of battery that can be recharged, given that sodium is a plentiful element on Earth and is more stable than lithium batteries. Consequently, there has been a growing body of research and development activity in this field. This article will describe the electrolytes in SIBs, which significantly contribute to the electrochemical and safety characteristics of SIBs. The electrolytes discussed will include liquid electrolyte, solid electrolyte, and solid-liquid composite electrolyte. The most common use of electrolytes in an organic solvent comprises sodium salt (NaPF6 or NaClO4) and carbonate. This electrolyte has been successfully matched with a range of anodes and cathodes, resulting in satisfactory overall performance. Nevertheless, the obvious drawback is corroding sodium metal electrodes over extended periods of use and potential safety concerns.