Electrochemical properties of tetrahydropyran-based ternary electrolytes for 4 V lithium metal rechargeable batteries

In order to improve low-temperature performance of ethylene carbonate (EC) + tetrahydropyran (THP) (5:5) electrolyte with 1 mol dm(-3) lithium bisperf luoroethylsulfonyl imide (LiN(SO2C2F5)(3) as solute, propylene carbonate (P C) solvent was mixed with this electrolyte. It was found that the electroch emical properties of the resultant ternary electrolytes depended strongly o n the solvent composition and 1 mol dm(-3) (LiN(SO2C2F5)(2))/EC + PC + THP (3:3:4) electrolyte had not only promising freezing point of -36 degreesC b ut also high lithium cycling efficiency of 95.2%. Furthermore, lithium cycl ing efficiency was improved to 99.0% by decreasing lithium deposition curre nt density to 0.2 mA cm(-2). At the temperature ranging from 25 to -10 degr eesC, Li/LiMn2O4 coin cell with 1 mol dm(-3) (LiN(SO2C2F5)(2))/ EC + PC + T HP (3:3:4) electrolyte showed the satisfactory cycling performance. Thermal tests further disclosed that this ternary electrolyte showed good thermal stability even with the existence of lithium metal. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.