Additive‐Assisted Hydrophobic Li⁺‐Solvated Structure for Stabilizing Dual Electrode Electrolyte Interphases through Suppressing LiPF₆Hydrolysis

Abstract

Lithium-metal batteries have attracted much attention due to their high energy density. However, the hydrolysis of LiPF₆ leads to uncontrollable Li dendrites growth and fast capacity fading. Herein, a hydrophobic Li⁺ -solvated structure is designed by inducing the hexafluoroisopropyl acrylate into the electrolyte system. Due to the alkene groups and non-polar perfluorocarbon (-CF₂ CF₂ CF₃ ) chain, a hydrophobic surface around Li-ion solvated aggregates can be obtained to protect the LiPF₆ against the attack from trace H₂ O. Moreover, the additive could also help to form an organic solid electrolyte interphase with rich polar C-F bonds, which can capture Li ions to restrain the dendrite growth. Therefore, the Li||Li symmetric cells show a stable cycling performance up to 500 h at a current density of 1 mA cm^-2 . The Li||LiNi_0.6 Co_0.2 Mn_0.2 O₂ cells show good cycling stability, exhibiting a specific capacity of 111 mAh g^-1 at 1 C with a capacity retention of 74 % after 200 cycles.