Additive-Assisted Hydrophobic Li+-Solvated Structure for Stabilizing Dual Electrode Electrolyte Interphases through Suppressing LiPF6 Hydrolysis

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 (-CF2CF2CF3) chain, a hydrophobic surface around Li-ion solvated aggregates can be obtained to protect the LiPF6 against the attack from trace H2O. 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||LiNi0.6Co0.2Mn0.2O2 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.

Automated summary

By introducing a hydrophobic Li+-solvated structure with a specific additive, the attack from water molecules on LiPF6 can be reduced, and the growth of lithium dendrites can be inhibited, leading to improved cycling stability and performance of lithium-metal batteries.