High-Safety Nonaqueous Electrolytes and Interphases for Sodium-Ion Batteries

Rapidly developed Na-ion batteries are highly attractive for grid energy storage. Nevertheless, the safety issues of Na-ion batteries are still a bottleneck for large-scale applications. Similar to Li-ion batteries (LIBs), the safety of Na-ion batteries is considered to be tightly associated with the electrolyte and electrode/electrolyte interphase. Although the knowledge obtained from LIBs is helpful, designing safe electrolytes and obtaining stable interphases in Na-ion batteries is still a huge challenge. Therefore, it is of significance to investigate the key factors and develop new strategies for the development of high-safety Na-ion batteries. This comprehensive review introduces the recent efforts from nonaqueous electrolytes and interphase aspects of Na-ion batteries, proposes their design strategies and requirements for improving safety characteristics, and discusses the potential issues for practical applications. The insight to formulate safe electrolytes and design the stable interphase for Na-ion batteries with high safety is intended to be provided herein.