Highly soluble organic nitrate additives for practical lithium metal batteries

Abstract

The stability of lithium metal anodes essentially dictates the lifespan of high-energy-density lithium metal batteries. Lithium nitrate (LiNO3) is widely recognized as an effective additive to stabilize lithium metal anodes by forming LiNxOy-containing solid electrolyte interphase (SEI). However, its poor solubility in electrolytes, especially ester electrolytes, hinders its applications in lithium metal batteries. Herein, an organic nitrate, isosorbide nitrate (ISDN), is proposed to replace LiNO3. ISDN has a high solubility of 3.3 M in ester electrolytes due to the introduction of organic segments in the molecule. The decomposition of ISDN generates LiNxOy-rich SEI, enabling uniform lithium deposition. The lifespan of lithium metal batteries with ISDN significantly increases from 80 to 155 cycles under demanding conditions. Furthermore, a lithium metal pouch cell of 439 Wh kg−1 delivers 50 cycles. This work opens a new avenue to develop additives by molecular modifications for practical lithium metal batteries.