Electrolyte solutions for anodes in rechargeable lithium batteries

The suitability of organic electrolyte systems for highly graphitized carbon anodes has been discussed by considering the stability of co-solvents included in ethylene carbonate-based electrolytes and the stability of lithium salts. The side-reaction and the film formation on the graphitized anodes were found to affect the discharge capacity of the graphitized anodes. With respect to the lithium salts, lithium bistrifluoromethylsulfonyl imide offered high and stable capacity. Furthermore, the electrochemical behavior of a surface film on a lithium metal anode was investigated at various operating temperatures. It was found that the operating temperature during charge/discharge cycling influences the morphology of the film on a lithium metal anode, resulting in the variation in charge/discharge coulombic efficiency of a lithium metal anode. The results are discussed in view of the stability of electrolyte solutions and the film formation between the negative electrode and the organic electrolyte solution.