A LiA1Cl4·3SO2-NaAlCl4·2SO2 binary inorganic electrolyte with improved electrochemical performance for Li-metal batteries

A LiAlCl 4 ·3SO 2 -NaAlCl 4 ·2SO 2 binary inorganic electrolyte was prepared by using NaAlCl 4 ·2SO 2 as the functional additive and mixing with LiAlCl 4 ·3SO 2 . The obtained LiAlCl 4 ·3SO 2 -NaAlCl 4 ·2SO 2 not only has good non-flammability but also exhibits improved electrochemical performance for Li-metal batteries. With the addition of NaAlCl 4 ·2SO 2 , the fabricated Li/Cu cells using mixed inorganic electrolyte display higher average coulombic efficiency and more excellent cycling stability. Through scanning electron microscopy (SEM) characterization, it is demonstrated that the surficial morphology of Li-deposited layer is smoother in LiAlCl 4 ·3SO 2 -NaAlCl 4 ·2SO 2 binary electrolyte system than pure LiAlCl 4 ·3SO 2 . Furthermore, the fabricated Li/graphite cells using LiAlCl 4 ·3SO 2 -NaAlCl 4 ·2SO 2 binary electrolyte also show higher specific capacity and better cycling stability than using pure LiAlCl 4 ·3SO 2 electrolyte as well as the conventional organic electrolyte (1 M LiPF 6 in ethylene carbonate/dimethyl carbonate mixed solvent with 1:1 in volume). Consequently, LiAlCl 4 ·3SO 2 -NaAlCl 4 ·2SO 2 is proposed to have great potential for the safe and high-performance Li-metal batteries. A LiAlCl 4 ·3SO 2 -NaAlCl 4 ·2SO 2 binary inorganic electrolyte is prepared by using NaAlCl 4 ·2SO 2 as the functional additive and mixing with LiAlCl 4 ·3SO 2 , which exhibits improved electrochemical performance for Li-metal batteries