Li metal anodes are extensively studied owing to their unparalleled advantages in achieving high energy density. However, safety issues originating from dendritic Li growth are always a huge hindrance for applications in Li metal batteries (LMBs). In this study, a functional additive, 4,6-dimethyl-2-mercaptopyrimidine (DMP), which is a typical leveler in the copper electroplating industry, is selected to suppress Li dendrite formation. Various Li-metal-based batteries are systematically investigated and they show stable performances, such as excellent cycling stability above 800 h at 3 mA cm⁻² in Li||Li cells and 400 cycles with high coulombic efficiencies (CEs >98%) at 1 mA cm⁻² in Li||Cu cells. Furthermore, a comprehensive verification of the protective mechanism induced by the DMP leveling agent shows that the leveler updated the Li⁺ solvation structure and occupied the inner Helmholtz plane of the Li anode. The planar DMP molecular layer absorbed on the surface of the Li metal can suppress side reactions and modify the Li deposition behavior via steric hindrance, inducing homogeneous Li deposition. Interestingly, the DMP leveler does not participate in the formation of the solid electrolyte interphase. This study can stimulate further ideas on non-depleting but effective levelers as electrolyte additives for high-performance LMBs.

中文翻译：

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作为电解质添加剂的非消耗性整平剂可实现均匀的锂沉积

锂金属负极因其在实现高能量密度方面具有无与伦比的优势而受到广泛研究。然而，枝晶锂生长引起的安全问题始终是锂金属电池（LMB）应用的巨大障碍。在本研究中，选择功能性添加剂4,6-二甲基-2-巯基嘧啶（DMP）来抑制锂枝晶的形成，它是铜电镀行业中的典型整平剂。系统研究了各种锂金属电池，它们表现出稳定的性能，例如Li||Li电池在3 mA cm ^-2下超过800小时的优异循环稳定性，以及在3 mA cm -2 下400次循环的高库伦效率（CE > 98%）。Li||Cu电池中1 mA cm ^{-2 。}此外，对DMP均化剂诱导的保护机制的全面验证表明，均化剂更新了Li ⁺溶剂化结构并占据了Li阳极的内亥姆霍兹平面。吸附在锂金属表面的平面DMP分子层可以抑制副反应，并通过空间位阻改变锂沉积行为，从而诱导均匀的锂沉积。有趣的是，DMP 整平剂不参与固体电解质界面的形成。这项研究可以激发关于非消耗但有效的整平剂作为高性能 LMB 电解质添加剂的进一步想法。