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

• Published in: Angewandte Chemie International Edition Vol. 61; no. 27; pp. e202205091 - n/a
• Main Authors: Li, Fang, Liu, Jiandong, He, Jian, Hou, Yuyang, Wang, Huaping, Wu, Daxiong, Huang, Junda, Ma, Jianmin
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 04.07.2022
• Edition: International ed. in English
• Subjects: Batteries; Cycles; Dendrites; Electrode Electrolyte Interphase; Electrolyte Additives; Electrolytic cells; Hydrolysis; Hydrophobic Surface; Hydrophobicity; Li Dendrites; Lithium; Lithium-Metal Batteries; Perfluorocarbons; Solid electrolytes; Specific capacity
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202205091

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. A hydrophobic Li+‐solvated structure is developed by inducing hexafluoroisopropyl acrylate (HFAC) into electrolytes, which can not only physically block the contact between PF6− and trace H2O, but also help to form an organic‐rich electrode electrolyte interphase to alleviate the growth of Li dendrites and improve the structural stability of the Ni‐rich cathode, resulting in improved cycling stability of Li‐metal batteries.