deterioration of battery performance the present invention employs a material that can form an sei film on a surface of the negative electrode during initial charging without gas generation and deterioration of the battery performance such a material hereinafter referred to as an u201c additive u201d may include a compound with s or p or a carbonate based compound the compound with s or p includes a s u2550 o bond or a p u2550 o bond in its molecular structure examples of the compound with s or p include vinyl sulfone so 2 gas and 1 3 propanesultone and an example of the carbonate based compound is vinylene carbonate alternatively a compound containing the sei film components may be used the additive when added to a negative active material composition prevents the reaction between the surface of the negative electrode and the electrolyte at initial charging thereby inhibiting gas generation which results in the prevention of an increase in thickness of the battery and a decrease in capacity the negative active material composition of the present invention includes one or more carbonaceous materials which are known as negative active materials that is any compound that advances an electrochemical redox reaction and in which intercalation and deintercalation of lithium ions reversibly occurs may be used examples of which include amorphous carbon and crystalline carbon the amorphous carbon may be soft carbon hard carbon a mesophase pitch carbonized material or coke the.