Dual fluorination of polymer electrolyte and conversion-type cathode for high-capacity all-solid-state lithium metal batteries

• Published in: Nature communications Vol. 13; no. 1; pp. 7914 - 17
• Main Authors: Hu, Jiulin, Lai, Chuanzhong, Chen, Keyi, Wu, Qingping, Gu, Yuping, Wu, Chenglong, Li, Chilin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.12.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/299; 639/4077; 639/4077/4079/891; 639/638/161; 639/638/675; Aluminum fluorides; Cycles; Discharge; Electrochemistry; Electrodes; Electrolytes; Electrolytic cells; Energy storage; Fluorination; Humanities and Social Sciences; Ion storage; Lithium; Lithium batteries; Lithium ions; Metal fluorides; multidisciplinary; Polymers; Science; Science (multidisciplinary); Solid electrolytes; Solid state; Storage batteries; Thickening
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-35636-0

All-solid-state batteries are appealing electrochemical energy storage devices because of their high energy content and safety. However, their practical development is hindered by inadequate cycling performances due to poor reaction reversibility, electrolyte thickening and electrode passivation. Here, to circumvent these issues, we propose a fluorination strategy for the positive electrode and solid polymeric electrolyte. We develop thin laminated all-solid-state Li||FeF 3 lab-scale cells capable of delivering an initial specific discharge capacity of about 600 mAh/g at 700 mA/g and a final capacity of about 200 mAh/g after 900 cycles at 60 °C. We demonstrate that the polymer electrolyte containing AlF 3 particles enables a Li-ion transference number of 0.67 at 60 °C. The fluorinated polymeric solid electrolyte favours the formation of ionically conductive components in the Li metal electrode’s solid electrolyte interphase, also hindering dendritic growth. Furthermore, the F-rich solid electrolyte facilitates the Li-ion storage reversibility of the FeF 3 -based positive electrode and decreases the interfacial resistances and polarizations at both electrodes. The practical use of all-solid-state batteries is hindered by inadequate cycling performance. Here, the authors propose a fluorination strategy for the positive electrode and polymeric electrolyte to develop all-solid-state Li||FeF3 pouch cells with high discharge capacity and long cycle life.