Huang Huayu, Liu Shishi, Xie Yuxiang, Liu Junke, Shi Chenguang, Sun Miaolan, Peng Hao, Lan Jian, Deng Ya-Ping, Huang Ling, Sun Shi-Gang
State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
J Am Chem Soc. 2024 Nov 13;146(45):31137-31149. doi: 10.1021/jacs.4c11012. Epub 2024 Nov 1.
The bottleneck of Li metal batteries toward practical applications lies at inferior cyclability as well as Li dendrite issues. As a promising solution, an interface engineering strategy is proposed herein for the Li anode through constructing a hybrid artificial interface. It is assembled onto the Li anode using photocontrolled free radical polymerization (photo-CRP) of polyethylene glycol diacrylate-hexafluorobutyl methacrylate and hexafluorobutyl methacrylate-trifluoroethyl carbonate (PEGDA-HFMBA@HFMBA-FEMC or PH@HF layer). Among such hybrid interfaces, the interior layer of PEGDA-HFMBA exists as a protective shield with flexibility and fracture resistance, while the exterior layer of HFMBA-FEMC plays a role as a LiF reservoir to promote Li mass transfer and its even electrodeposition. In the meantime, some excess HFMBA and FEMC monomers further dissolve into the electrolyte as molecular additives, followed by in situ generation of a thin and robust LiF-rich cathode electrolyte interface (CEI). With the resulting Li anode, Li/NCM811 full cells showcase multifold cyclability amplification in comparison to cells using Bare-Li, covering durable cyclability with a capacity retention of 81.8% after 400 cycles. When the cutoff voltage is elevated to 4.5 V or the working temperature is elevated to 45 °C, the cells still maintain a stable operation for extending 300 cycles.
锂金属电池在实际应用中的瓶颈在于循环性能较差以及锂枝晶问题。作为一种有前景的解决方案，本文提出了一种通过构建混合人工界面来对锂负极进行界面工程的策略。它是利用聚乙二醇二丙烯酸酯 - 甲基丙烯酸六氟丁酯和甲基丙烯酸六氟丁酯 - 三氟乙基碳酸酯的光控自由基聚合（光引发可控自由基聚合）组装在锂负极上的（聚乙二醇二丙烯酸酯 - 甲基丙烯酸六氟丁酯@甲基丙烯酸六氟丁酯 - 三氟乙基碳酸酯或PH@HF层）。在这种混合界面中，聚乙二醇二丙烯酸酯 - 甲基丙烯酸六氟丁酯的内层作为具有柔韧性和抗断裂性的保护屏障存在，而甲基丙烯酸六氟丁酯 - 三氟乙基碳酸酯的外层则作为LiF储库，促进锂的质量传递及其均匀电沉积。同时，一些过量的甲基丙烯酸六氟丁酯和三氟乙基碳酸酯单体进一步作为分子添加剂溶解到电解质中，随后原位生成一层薄而坚固的富含LiF的阴极电解质界面（CEI）。使用所得的锂负极，与使用裸锂的电池相比，Li/NCM811全电池的循环性能提高了数倍，在400次循环后具有81.8%的容量保持率，展现出持久的循环性能。当截止电压提高到4.5 V或工作温度提高到45°C时，电池仍能保持稳定运行并延长300次循环。
