Lithium metal batteries (LMBs) employing high-voltage nickel-rich cathodes represent a promising strategy to enable higher energy density storage systems. However, instability at the electrolyte–electrode interfaces (EEIs) currently impedes the translation of these advanced systems into practical applications. Herein, 1,3-dimethyl-1H-imidazol-2(3H)-one (DMIO), integrating structural features of vinylene carbonate (VC) while substituting oxygen with electron-donating nitrogen, has been synthesized and validated as a multifunctional electrolyte additive for high-voltage LMBs. Theoretical calculations and experimental results demonstrate that the potent electron-donating nitrogen in DMIO enables preferential DMIO oxidation at the cathode while preserving its carbon–carbon double bond for a concomitant reduction on the anode. Thereby, robust DMIO-derived EEIs are generated, reinforcing cycling in the full cells. Additionally, DMIO leverages Lewis acid-based interactions to coordinate and sequester protons from acidic LiPF₆ decomposition byproducts, concurrently retarding LiPF₆ hydrolysis while attenuating parasitic consumption of EEIs by acidic species. Consequently, incorporating DMIO into conventional carbonate electrolytes enables an improved capacity retention of Li||NCM622 cells to 81% versus 26% in the baseline electrolyte after 600 cycles. Similarly, DMIO improves Li anode cycling performance, displaying extended life spans over 200 h in Li||Li symmetric cells and enhancing Coulombic efficiency from 76% to 88% in Li||Cu cells. The synergistic effects of DMIO on both the cathode and anode lead to substantially improved cell lifetime. This rationally designed, multifunctional electrolyte additive paradigm provides vital insights that can be translatable to further electrolyte molecular engineering strategies.

中文翻译：

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碳酸亚乙烯酯启发的1,3-二甲基-1H-咪唑-2(3H)-一添加剂的合理设计稳定高压锂金属电池

采用高压富镍阴极的锂金属电池（LMB）是实现更高能量密度存储系统的一种有前景的策略。然而，电解质-电极界面（EEI）的不稳定性目前阻碍了这些先进系统转化为实际应用。在此，合成了1,3-二甲基-1H-咪唑-2(3H ) -酮(DMIO)，它综合了碳酸亚乙烯酯(VC)的结构特征，同时用给电子氮取代了氧，并被验证为多功能化合物。用于高压 LMB 的电解液添加剂。理论计算和实验结果表明，DMIO 中有效的给电子氮使得 DMIO 在阴极优先氧化，同时保留其碳-碳双键，从而在阳极同时发生还原。因此，产生了强大的 DMIO 衍生 EEI，增强了全细胞的循环。此外，DMIO 利用基于路易斯酸的相互作用来协调和隔离酸性 LiPF ₆分解副产物中的质子，同时延迟 LiPF ₆水解，同时减少酸性物质对 EEI 的寄生消耗。因此，在传统碳酸盐电解质中加入 DMIO 可以将 Li||NCM622 电池在 600 次循环后的容量保持率提高至 81%，而基线电解质中的容量保持率为 26%。同样，DMIO 改善了 Li 阳极循环性能，在 Li||Li 对称电池中显示出超过 200 小时的延长寿命，并将 Li||Cu 电池中的库仑效率从 76% 提高到 88%。DMIO 对阴极和阳极的协同效应可显着提高电池寿命。这种合理设计的多功能电解质添加剂范例提供了重要的见解，可以转化为进一步的电解质分子工程策略。