Retuning Solvating Ability of Ether Solvent by Anion Chemistry toward 4.5 V Class Li Metal Battery
Retuning Solvating Ability of Ether Solvent by Anion Chemistry toward 4.5 V Class Li Metal Battery
复制标题
DOI：
10.1002/adfm.202310516
复制
发表时间：
2023-11
影响因子：
19
通讯作者：
Dandan Chai;Haotian Yan;Xin Wang;Xiang Li;Yongzhu Fu
中科院分区：
文献类型：
--
作者：
Dandan Chai;Haotian Yan;Xin Wang;Xiang Li;Yongzhu Fu
醚基电解质与锂金属具有良好的相容性，广泛应用于锂金属电池（LMB）。然而，由于其抗氧化性能较差，该电解质不适合高电压（>4.0 V）。在此，针对具有 1 m 双（氟磺酰基）亚胺锂（LiFSI）的典型 1,2-二甲氧基乙烷（DME）基电解质设计了阴离子化学策略，通过使用具有高供体数（DN）值的硝酸根阴离子（NO3−）来调节 DME 和 FSI– 的配位。事实证明，由于NO3−的竞争优势，它们之间的相互作用减弱，因此形成了弱溶剂化电解质。它促进阴极上富含无机物的钝化层的形成，并促进去溶剂化过程，因此即使在4.5 V也适用于高电压。这里设计的阴离子调节弱溶剂化电解质（ARWSE）不同于高浓度电解质（HCE）、局部HCE和WSE，它们成本高且复杂。 ARWSE 被证明是一种可调节电解质系统，可有效改善 LMB 的界面化学。
Ether‐based electrolytes have good compatibility for lithium metal, which is widely used in lithium metal batteries (LMBs). However, the electrolyte is not suitable for high voltage (>4.0 V) due to its poor anti‐oxidation behavior. Herein, an anion chemistry strategy is designed for a typical 1,2‐dimethoxyethane (DME)‐based electrolyte with 1 m lithium bis(fluorosulfonyl)imide (LiFSI), by using nitrate anion (NO3−) with a high donor number (DN) value to regulate the coordination of DME and FSI–. It is evidenced that the interaction between them is weakened due to the competitive advantage of NO3−, therefore a weakly solvating electrolyte is achieved. It promotes the formation of an inorganic‐rich passivation layer on the cathode and facilitates the de‐solvation process, thus it is suitable for high voltage even at 4.5 V. The anion‐regulated weakly solvating electrolyte (ARWSE) designed here is different from the high‐concentration electrolyte (HCE), localized HCE, and WSE which are of high cost and complexity. The ARWSE is demonstrated to be an adjustable electrolyte system, effectively improving the interfacial chemistry of LMBs.