In situ fluorinated solid electrolyte interphase towards long-life lithium metal anodes

Abstract

The urgent demands for high-energy-density rechargeable batteries promote a flourishing development of Li metal anode. However, the uncontrollable dendrites growth and serious side reactions severely limit its commercial application. Herein, an artificial LiF-rich solid electrolyte interphase (SEI) is constructed at molecular-level using one-step photopolymerization of hexafluorobutyl acrylate based solution, where the LiF is in situ generated during photopolymerization process (denoted as PHALF). The LiF-rich layer comprised flexible polymer matrix and inorganic LiF filler not only ensures intimate contact with Li anode and adapts volume fluctuations during cycling but also regulates Li deposition behavior, enabling it to suppress the dendrite growth and block side reactions between the electrolyte and Li metal. Accordingly, the PHALF-Li anode presents superior stable cycling performance over 500 h at 1 mA·cm−2 for 1 mA·h·cm−2 without dendrites growth in carbonate electrolyte. The work provides a novel approach to design and build in situ artificial SEI layer for high-safety and stable Li metal anodes.