Recently, Prof. Wang Feng, Prof. Niu Jin, and co-workers from CMSE published a paper entitled An ultrathin solid electrolyte for high-energy lithium metal in the high-impact journal of Advanced Functional Materials. Solid-state electrolytes (SSEs) are key to unlocking the potential of lithium metal batteries (LMBs), but their high thickness (>100 µm) due to poor mechanical properties limits energy density improvements. In this work, an ultrathin (≈5 µm) polymer SSE with a high Young's modulus (10.6 GPa), made from a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) matrix and an ethylene diamine tetraacetic acid (EDTA) additive is proposed. By virtue of the electron-donating property, EDTA induces the conformation transformation of PVDF-HFP, enhancing the mechanical strength by a fine-grain strengthening mechanism. In addition, PVDF-HFP with cis-conformation shortens the pathway for Li+, promotes the Li+ dissociation and immobilizes the anions of lithium salt, thus increasing the ionic conductivity (2.47 × 10−4 S cm−1) and transfer number (0.59) of the electrolyte. Moreover, the electrolyte also possesses a wide voltage window (4.7 V) and good heat/flame resistance. The half cells and full cells with the electrolytes show good cycling and rate performance. Notably, a pouch cell based on the electrolyte exhibits impressive energy densities of 516 Wh kg−1 and 1520 Wh L−1 (excluding packages), showing great potential for practical use in LMBs.
The first author of this paper is Liu Lufan, a master student in CMSE. Prof. Wang Feng and Prof. Niu Jin are the co-corresponding authors. Beijing University of Chemical Technology is the first completion unit. This research work has been supported by several projects such as the National Key Research and Development Program of China and National Natural Science Foundation of China.
Article information：Lufan Liu, Yongzheng Shi, Mengyue Liu, Qing Zhong, Yuqi Chen, Bingyang Li, Zhen Li, Tao Zhang, Hang Su, Jiaying Peng, Na Yang, Pengfei Wang, Adrian Fisher, Jin Niu, Feng Wang. An ultrathin solid electrolyte for high-energy lithium metal batteries. 2024, Adv. Funct. Mater., DOI: 10.1002/adfm.202403154.
