Non-flammable nonaqueous electrolyte solution and lithium ion cell using same

Abstract

Disclosed are a non-flammable nonaqueous electrolyte solution and a lithium ion cell using the electrolyte solution. The non-flammable nonaqueous electrolyte solution comprises a ternary or higher-order compound additive, a high concentration of lithium salt and a phosphoric ester serving as a primary solvent. The lithium ion cell comprises a positive electrode containing a lithium transition metal oxide capable of absorbing and releasing lithium, a negative electrode containing a carbon-based material capable of absorbing and releasing lithium, and the above non-flammable nonaqueous electrolyte solution. The ternary or higher-order compound additive contains at least one compound selected from each of the three compound groups consisting of: a compound group (a) of vinylene carbonate compounds; a compound group (b) of vinyl acetate compounds, alkyl methyl carbonate compounds and vinyl ethylene carbonate compounds; and a compound group (c) of 2-pyrrolidinone compounds, cyclic alkyl compounds and cyclic pentanone compounds. The non-flammable nonaqueous electrolyte solution of the present invention can provide enhanced charge/discharge characteristics to a lithium ion cell.