Achieving Uniform Li Deposition and Suppressed Electrolyte Flammability in Li‐Metal Batteries via Designing Localized High‐Concentration Electrolytes

Abstract The increasing need for energy storage devices with high energy density has led to significant interest in Li‐metal batteries (LMBs). However, the use of commercial electrolytes in LMBs is problematic due to their flammability, inadequate performance at low temperatures, and tendency to promote the growth of lithium dendrites and other flaws. This study introduces a localized high‐concentration electrolyte (LHCE) that addresses these issues by employing non‐flammable electrolyte components and incorporating carefully designed additives to enhance flame retardancy and low‐temperature performance. By incorporating additives to optimize the electrolyte, it is possible to attain inorganic‐dominated solid electrolyte interphases on both the cathode and anode. This achievement results in a uniform deposition of lithium, as well as the suppression of electrolyte decomposition and cathode deterioration. Consequently, this LHCE achieve over 300 stable cycles for both LiNi_0.9Mn_0.05Co_0.05O₂||Li cells and LiCoO₂||Li cells, as well as 50 cycles for LiNi_0.8Mn_0.1Co_0.1O₂ (NCM811||Li) pouch cells. Furthermore, NCM811||Li cells maintain 84% discharge capacity at −20 °C, in comparison to the capacity at room temperature. The utilization of this electrolyte presents novel perspectives for the safe implementation of LMBs.