Enhanced Low‐Temperature Resistance of Lithium‐Metal Rechargeable Batteries Based on Electrolyte Including Ethyl Acetate and LiDFOB Additives

Abstract

AbstractTo meet the demand for higher energy density in lithium‐ion batteries and expand their application range, coupling lithium metal anodes with high‐voltage cathodes is an ideal solution. However, the compatibility between lithium metal batteries and electrolytes affects their applicability. In this study, proposes a locally concentrated electrolyte based on ethyl acetate (EA) as the solvent, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as the lithium salt, and lithium difluorooxoborate (LiDFOB) as a sacrificial agent to enhance the low‐temperature and high‐voltage endurance of Li//Lithium cobalt oxide (LCO) batteries. The Li//LCO battery can operate within the voltage range of 3 to 4.5 V, with an initial discharge specific capacity of 174.5 mAh g−1 at 20 °C. At −40 °C, after 200 cycles, the capacity retention rate is 87.7 %. It can operate under extreme conditions of −70 °C, with a discharge specific capacity of 112.6 mAh g−1. Additionally, LCO//HC batteries using this electrolyte demonstrate excellent performance. Present work provides a new perspective for the optimization of electrolytes for low‐temperature lithium‐ion batteries.