US Patent 7608364 Lithium ion secondary battery

This invention provides a lithium ion secondary battery comprising a cathode, an anode and an nonaqueous electrolytic solution in which an electrolyte is dissolved in a nonaqueous solvent, wherein the anode comprises a non-graphitizable carbon as an anode activator; and the nonaqueous electrolytic solution comprises at least one anode protecting component selected from the group consisting of sultones having a 5- to 7-membered cyclic sulfonate structure and their substituted derivatives as well as vinylene carbonates and their substituted derivatives.