Japan Aerospace Exploration Agency

Kenichi Kuwajima

Yoshitsugu Sone

Xianming Wang

Saburo Kuwajima

Disclosed are an additive for improving charge/discharge characteristics of a lithium-ion cell, a nonaqueous electrolytic solution containing the additive, and a lithium-ion cell using the additive and/or the nonaqueous electrolytic solution. The additive serves as a solvent for a fluorine resin, such as poly(vinylidene fluoride), which is incorporated as an adhesive in a positive electrode containing a lithium-transition metal oxide capable of absorbing and releasing lithium and a negative electrode containing a carbon material capable of absorbing and releasing lithium. The additive comprises three compounds selected, respectively, from a 2-pyrrolidinone compound group, a cyclic alkyl compound group, and a cyclic pentanone compound group.

Nonaqueous electrolytic solution containing additive for increasing capacity of lithium-ion cell and lithium-ion cell using same

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.

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Kanagawa, Japan

Kenichi Kuwajima