LLZO@EmimFSI@PEO derived hybrid solid electrolyte for high-energy lithium metal batteries

Although all-solid-state batteries have good safety and high energy density, they still need to explore high performance solid-state electrolytes to achieve high ionic conductivity, wide electrochemical window and excellent mechanical properties. In this work, we designed a hybrid solid electrolyte to solve these problems via mixing PEO, ionic liquid EmimFSI (1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide), LLZO (Li6.5Mg0.05La3Zr1.6Ta0.4O12) and lithium salt, which aimed at suppression of PEO crystallization and employed to improve the mechanical and electrochemical stability. Accordingly, the LLZO@EmimFSI@PEO derived hybrid solid electrolyte provides an ionic conductivity of 1.0×10-4 S cm-1 at 40oC and electrochemical stability window above 5.0 V vs. Li/Li+. Furthermore, the symmetric cell of Li/hybrid solid electrolyte/Li exhibits flat voltage profiles and stable lithium plating/stripping process, a solid-state battery based on the hybrid solid electrolyte combined with high-energy lithium metal anode and NCM622 (LiNi0.6Co0.2Mn0.2O2) cathode was also demonstrated.