Li Fang, Liu Jiandong, He Jian, Hou Yuyang, Wang Huaping, Wu Daxiong, Huang Junda, Ma Jianmin
School of Physics and Electronics, Hunan University, Changsha, 410082, China.
Science Center for Materials Creation and Energy Conversion, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, 266237, China.
Angew Chem Int Ed Engl. 2022 Jul 4;61(27):e202205091. doi: 10.1002/anie.202205091. Epub 2022 May 12.
Lithium-metal batteries have attracted much attention due to their high energy density. However, the hydrolysis of LiPF 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 (-CF CF CF ) chain, a hydrophobic surface around Li-ion solvated aggregates can be obtained to protect the LiPF against the attack from trace H 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 . The Li||LiNi Co Mn O cells show good cycling stability, exhibiting a specific capacity of 111 mAh g at 1 C with a capacity retention of 74 % after 200 cycles.
锂金属电池因其高能量密度而备受关注。然而，LiPF的水解会导致锂枝晶生长失控和快速的容量衰减。在此，通过将丙烯酸六氟异丙酯引入电解质体系设计了一种疏水锂溶剂化结构。由于烯烃基团和非极性全氟碳链（-CF₂CF₂CF₃），可以在锂离子溶剂化聚集体周围获得疏水表面，以保护LiPF免受痕量H₂O的攻击。此外，该添加剂还有助于形成具有丰富极性C-F键的有机固体电解质界面，其可以捕获锂离子以抑制枝晶生长。因此，Li||Li对称电池在1 mA cm⁻²的电流密度下表现出高达500 h的稳定循环性能。Li||LiNi₀.₈Co₀.₁Mn₀.₁O₂电池表现出良好的循环稳定性，在1 C下的比容量为111 mAh g⁻¹，200次循环后的容量保持率为74%。
