Li Qi, Zhang Xiaoyu, Peng Jian, Wang Zhihao, Rao Zhixiang, Li Yuyu, Li Zhen, Fang Chun, Han Jiantao, Huang Yunhui
State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Optoelectronic Materials & Technology, Jianghan University, Wuhan, Hubei 430056, People's Republic of China.
ACS Appl Mater Interfaces. 2022 May 11;14(18):21018-21027. doi: 10.1021/acsami.2c02731. Epub 2022 Apr 28.
Poly(ethylene oxide) (PEO)-based polymer electrolytes have been widely studied as a result of their flexibility, excellent interface contact, and high compatibility with a lithium metal anode. Owing to the poor oxidation resistance of ethers, however, the PEO-based electrolytes are only compatible with low-voltage cathodes, which limits their energy density. Here, a high-voltage stable solid-state interface layer based on polyfluoroalkyl acrylate was constructed via solvent-free bulk electropolymerization between the LiNiMnCoO (NCM811) cathode and the PEO-based solid polymer electrolyte. The electrochemical oxidation window of the as-synthesized electrolyte was therefore expanded from 4.3 V for the PEO-based matrix electrolyte to 5.1 V, and the ionic conductivity was improved to 1.02 × 10 S cm at ambient temperature and 4.72 × 10 S cm at 60 °C as a result of the improved Li migration. This fabrication process for the interface buffer layer by an electrochemical process provides an innovative and universal interface engineering strategy for high-performance and high-energy-density solid-state batteries, which has not been explicitly discussed before, paving the way toward the large-scale production of the next generation of solid-state lithium batteries.
聚环氧乙烷（PEO）基聚合物电解质因其柔韧性、优异的界面接触性以及与锂金属负极的高兼容性而受到广泛研究。然而，由于醚类的抗氧化性较差，PEO基电解质仅与低压正极兼容，这限制了它们的能量密度。在此，通过在LiNiMnCoO（NCM811）正极和PEO基固体聚合物电解质之间进行无溶剂本体电聚合，构建了基于聚丙烯酸氟烷基酯的高压稳定固态界面层。因此，合成电解质的电化学氧化窗口从PEO基基体电解质的4.3 V扩大到5.1 V，并且由于锂迁移的改善，离子电导率在室温下提高到1.02×10⁻³ S cm⁻¹，在60°C时提高到4.72×10⁻³ S cm⁻¹。这种通过电化学过程制备界面缓冲层的方法为高性能和高能量密度固态电池提供了一种创新且通用的界面工程策略，此前尚未有明确讨论，为下一代固态锂电池的大规模生产铺平了道路。
