Ion-Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries.
Ion-Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries.
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DOI：
10.1021/jacs.3c07482
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发表时间：
2023-11
影响因子：
15
通讯作者：
Menglu Li;Hanwen An;Yajie Song;Qingsong Liu;Jian Wang;Hua Huo;Shuaifeng Lou;Jiajun Wang
中科院分区：
文献类型：
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作者：
Menglu Li;Hanwen An;Yajie Song;Qingsong Liu;Jian Wang;Hua Huo;Shuaifeng Lou;Jiajun Wang
聚偏氟乙烯（PVDF）电解质具有较高的离子电导率和机械强度，在固态锂电池中的应用越来越受到人们的关注，但高活性残留溶剂严重影响了其循环稳定性。在这里，我们报告了一个自由溶剂捕获策略引发的增强离子偶极相互作用之间的Li+和残留的溶剂分子。具有吸电子能力的二氟硼酸锂（LiDFOB）盐添加剂充当Li+正电性状态的再分配器，其为残留溶剂提供更多结合位点。得益于改性的配位环境，优先形成动力学稳定的阴离子衍生的界面，有效地减轻了电极和电解质之间的界面副反应。结果，组装的固态电池显示出超过2000次循环的寿命，平均库仑效率为99.9%，容量保持率为80%。我们的发现为有针对性地调节反应性残留溶剂以延长固态电池的循环寿命提供了新的思路。
Owing to high ionic conductivity and mechanical strength, poly(vinylidene fluoride) (PVDF) electrolytes have attracted increasing attention for solid-state lithium batteries, but highly reactive residual solvents severely plague cycling stability. Herein, we report a free-solvent-capturing strategy triggered by reinforced ion-dipole interactions between Li+ and residual solvent molecules. Lithium difluoro(oxalato)borate (LiDFOB) salt additive with electron-withdrawing capability serves as a redistributor of the Li+ electropositive state, which offers more binding sites for residual solvents. Benefiting from the modified coordination environment, the kinetically stable anion-derived interphases are preferentially formed, effectively mitigating the interfacial side reactions between the electrodes and electrolytes. As a result, the assembled solid-state battery shows a lifetime of over 2000 cycles with an average Coulombic efficiency of 99.9% and capacity retention of 80%. Our discovery sheds fresh light on the targeted regulation of the reactive residual solvent to extend the cycle life of solid-state batteries.