A novel lithium salt with a chelate compound of phosphorus for lithium battery electrolytes

We have synthesized a novel Li salt with a chelate compound of phosphorus, lithium tris[4-methyl-1,2-benzenediolato(2-)-O,O']phosphate (4-MLTBP). The thermal stability and electrolytic properties of 4-MLTBP, and the charge-di scharge characteristics of a lithium electrode are investigated. The therma l decomposition temperature of 4-MLTBB is higher than those of a common lit hium salt with phosphorus, LiPF6, and lithium tris [1,2-benzenediolato(2-)- O,O']phosphate, which we previously synthesized. The specific conductivitie s and the cycling efficiencies become higher in an ethylene carbonate- and a propylene carbonate-dimethyl carbonate equimolar binary solutions contain ing a mixture of 4-MLTPB with LiPF6.