Lithium metal anodes are steadily gaining more attention, as their superior specific capacities and low redox voltage can significantly increase the energy density of rechargeable batteries far beyond those of current Li‐ion batteries. Nonetheless, the relevant technology is still in a premature research stage mainly due to the uncontrolled growth of Li dendrites that ceaselessly cause unwanted side reactions with electrolyte. In order to circumvent this shortcoming, herein, an ionic liquid additive, namely, 1‐dodecyl‐1‐methylpyrrolidinium (Pyr1(12)⁺) bis(fluorosulfonyl)imide (FSI⁻), for conventional electrolyte solutions is reported. The Pyr1(12)⁺ cation with a long aliphatic chain mitigates dendrite growth via the combined effects of electrostatic shielding and lithiophobicity, whereas the FSI⁻ anion can induce the formation of rigid solid–electrolyte interphase layers. The synergy between the cation and anion significantly improves cycling performance in asymmetric and symmetric control cells and a full cell paired with an LiFePO₄ cathode. The present study provides a useful insight into the molecular engineering of electrolyte components by manipulating the charge and structures of the involved molecules.

中文翻译：

---

锂金属阳极离子液体添加剂的阳离子和阴离子的协同作用

锂金属阳极一直在受到越来越多的关注，因为其优异的比容量和低氧化还原电压可以显着提高可充电电池的能量密度，远远超过目前的锂离子电池。尽管如此，相关技术仍处于过早的研究阶段，这主要是由于Li树枝状晶体的不受控制的生长，不断地引起与电解质的不良副反应。为了规避这个缺点，在此，离子液体添加剂，即，1-十二烷基-1-甲基吡咯烷（PYR1（12）⁺）双（氟磺酰）亚胺（FSI ^- ），对于传统的电解质溶液被报告。Pyr1（12）⁺阳离子与长链脂族链减轻经由静电屏蔽和lithiophobicity的组合效应的枝晶生长，而FSI ^-阴离子可诱导刚性固体电解质的界面层的形成。阳离子和阴离子之间的协同作用显着改善了不对称和对称控制电池以及与LiFePO ₄阴极配对的完整电池的循环性能。本研究通过操纵所涉及分子的电荷和结构，为电解质组分的分子工程学提供了有用的见识。