Application of High-Voltage Ether-Based Electrolytes in High-Voltage Lithium Metal Batteries

Abstract

The theoretical energy density of traditional lithium-ion batteries is close to its theoretical upper limit, and it is difficult to meet the endurance needs of future electric vehicles. In contrast, lithium metal negative electrode with its theoretical specific capacity of up to 3860 mAh/g, especially when matched with high voltage nickel-rich positive electrode (such as NCM), its energy density is expected to reach more than twice that of traditional graphite-based lithium-ion batteries, so it is considered to be one of the most potential candidates for the next generation of high energy density battery systems. However, the unstable solid electrolyte interface (SEI) between lithium metal and electrolyte seriously restricts its cycling performance. Lithium nitrate (LiNO3), as a commonly used additive for lithium metal negative electrode, plays an important role in lithium metal batteries. By forming anion-derived SEI layer rich in inorganic components such as Li3N, interface stability can be significantly improved, but its solubility in carbonate solvents is limited. Ether-based solvents have attracted much attention in LiNO3-based electrolyte because of their moderate DN value and good compatibility with lithium metal.