Liu Zheng, Tu Haifeng, Wang Zhicheng, Xue Jiangyan, Ding Peng, Zhang Haiyang, Gao Yiwen, Yang Yi, Wu Guangye, Lu Suwan, Liu Lingwang, Wang Qing, Kang Byoungwoo, Xu Jingjing, Li Hong, Wu Xiaodong
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
i-lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
Small. 2025 Jun;21(25):e2503417. doi: 10.1002/smll.202503417. Epub 2025 May 2.
Locally concentrated ionic liquid electrolytes (LCILEs) are promising electrolyte systems for lithium metal batteries (LMBs) due to their robust anion-derived solid electrolyte interphase (SEI) and compatibility with Ni-rich cathodes. Low-halogen-content chlorides, with low price and weakly coordinating ability to Li, emerge as exceptional candidates for diluents in LCILEs. Here, it is demonstrated that the anti-reduction capability of chloride-based diluent in LCILEs significantly affects the stability of the Li anode. Typically, 1,4-dichlorobutane (DCB14) and 1,5-dichloropentane (DCP15) possess high electrophilicity, making them susceptible to electron attack and prone to severe side reactions with Li metal anode. In contrast, 2,2-dichlorodiethyl ether (DCDEE), where an oxygen atom replaces the central carbon atom in DCP15, demonstrates excellent reduction stability as it constitutes an electron-rich system with low electrophilicity. In LCILE with DCDEE diluent, the weak coordination interaction of DCDEE facilitates Li ion transport, while the resulting dual-halide LiF/LiCl hybrid electrode-electrolyte interphases (EEIs) effectively enhance the stability of electrodes. Consequently, Li||Cu cells sustain up to 740 cycles with a high coulombic efficiency (CE) of 99%. Furthermore, 1.2 Ah Li||LiNiCoMnO (NCM90) pouch cells are assembled to assess practical applicability, which exhibit impressive cycling stability with a high CE of 99.8%.
局部浓缩离子液体电解质（LCILEs）因其强大的阴离子衍生固体电解质界面（SEI）以及与富镍阴极的兼容性，成为锂金属电池（LMBs）颇具前景的电解质体系。低卤素含量的氯化物价格低廉且对锂的配位能力较弱，成为LCILEs中稀释剂的优异候选物。在此，研究表明LCILEs中基于氯化物的稀释剂的抗还原能力显著影响锂阳极的稳定性。通常，1,4 - 二氯丁烷（DCB14）和1,5 - 二氯戊烷（DCP15）具有较高的亲电性，使其易受电子攻击并易于与锂金属阳极发生严重的副反应。相比之下，2,2 - 二氯二乙醚（DCDEE）中一个氧原子取代了DCP15中的中心碳原子，由于其构成了一个亲电性低的富电子体系，表现出优异的还原稳定性。在含有DCDEE稀释剂的LCILE中，DCDEE的弱配位相互作用促进了锂离子传输，而形成的双卤化物LiF/LiCl混合电极 - 电解质界面（EEIs）有效地增强了电极的稳定性。因此，Li||Cu电池在高达99%的高库仑效率（CE）下可持续循环740次。此外，组装了1.2 Ah的Li||LiNiCoMnO（NCM90）软包电池以评估实际适用性，其在99.8%的高CE下表现出令人印象深刻的循环稳定性。
