Sodium-Ion Batteries: Exploration of Electrolyte Materials

Abstract

In recent years, as fossil energy sources such as oil and coal continue to be consumed, the issue of resources and the environment has become one of the main challenges to the sustainable development of human society. People's electricity consumption has increased dramatically, and the demand for energy storage batteries has also increased. Sodium-ion batteries (SIBs) are a very worthwhile development because of high Na reserves in the world, which can bring many advantages. The electrolyte can control the battery's inherent electrochemical window and performance, influence the nature of the electrode/electrolyte interface, and is one of the most important material choices for SIBs. The electrolyte simultaneously influences the electrochemical performance and safety of SIBs. This paper focuses on electrolyte materials in SIBs, explaining the fundamental needs and categorization of sodium ion electrolytes and highlighting the most recent advances in liquid and solid electrolytes. It is found that SIBs still have problems such as lower energy density, narrower electrochemical stability windows, poorer solid electrolyte interphase (SEI) stability, etc. Solving the related technical problems is of great significance for commercializing SIBs.