Plasma-strengthened ionic conducting network enabling highly safety separator toward all-climate lithium metal batteries

Abstract

Lithium metal batteries (LMBs) have been a promising candidate for high-energy–density energy storage system due to its high theoretical capacity and low density of metallic lithium (Li) anode, yet it still faces high risk of internal short circuits induced by thermal shrinkage and dendrite puncture of conventional polypropylene (PP) separators. To address these issues, an artificial interface, namely “plasma-strengthened ionic conducting network”, is constructed on the commercial PP separator, integrating high thermal/mechanical advantages of superionic Li1.5Al0.5Ge1.5(PO4)3 (LAGP) and chemical regulation of plasma-introduced F-contained groups (F-LAGP@PP). The high safety F-LAGP@PP can reduce risk of the short circuit of LMBs. Time-of-flight Secondary Ion Mass Spectrometry (Tof-SIMS) indicates the plasma-introduced F-contained groups can react with Li anode to generate a LiF-rich interphase to promote a high chemical stability of LAGP. Consequently, this easy-to-commercialize fabrication separator enables both LMBs and Li-ion full pouch cells to achieve high safety and appreciable electrochemical performance in a wide temperature range (–20–120 °C), highlighting its application prospect for advanced energy storage systems.