Fuji Jukogyo Kabushiki Kaisha

Atsuro Shirakami

Nobuo Ando

Kohei Matsui

Shinichi Tasaki

Yukinori Hato

Mitsuru Nagai

Kenji Kojima

Osamu Hatozaki

Hiromoto Taguchi

Risa Miyagawa

Risa Takahata

A lithium ion capacitor includes a positive electrode, a negative electrode, and a non-protonic organic solvent electrolytic solution of a lithium salt. A positive electrode active material is a material capable of reversibly doping a lithium ion and/or an anion. A negative electrode active material is a material capable of reversibly doping a lithium ion. The lithium ion is doped in advance to either one or both of the negative electrode and the positive electrode so that a positive electrode potential after the positive electrode and the negative electrode are short-circuited is 2.0 V (relative to Li/Li) or less when capacitance per unit weight of the positive electrode is C(F/g), weight of the positive electrode active material is W(g), capacitance per unit weight of negative electrode is C(F/g), and weight of the negative electrode active material is W(g), a value of (C&#xd7;W)/(C&#xd7;W) is 5 or more.

Lithium ion capacitor

A lithium ion capacitor includes a positive electrode made of a material capable of reversibly carrying either one or both of a lithium ion and an anion, a negative electrode made of a material capable of reversibly carrying a lithium ion, and an electrolytic solution made of a non-protonic organic solvent electrolytic solution of a lithium salt. A negative electrode active material is non-graphitizable carbon having a ratio of number of hydrogen atoms to number of carbon atoms of zero or more and less than 0.05. The lithium ion is doped in advance to either one or both of the negative electrode and the positive electrode so that a negative electrode potential when a cell is discharged to a voltage one half a charging voltage of the cell is 0.15 V or less relative to a lithium ion potential.

A lithium ion capacitor having a high capacity retention at the time of continuous charge at a high temperature and excellent durability. The lithium ion capacitor includes a positive electrode, a negative electrode and an aprotic organic solvent electrolyte solution of a lithium salt as an electrolytic solution. The positive electrode active material is a material capable of reversibly supporting lithium ions and/or anions, a negative electrode active material is a material capable of reversibly supporting lithium ions, the negative electrode and/or the positive electrode is doped with lithium ions so that the potential of the positive electrode is at most 2.0 V after the positive electrode and the negative electrode are short-circuited, and the electrolytic solution contains vinylene carbonate or its derivative.

A lithium ion capacitor including a positive electrode, a negative electrode, and an aprotic organic solvent solution of a lithium salt as an electrolytic solution. The positive electrode active material is capable of reversibly supporting lithium ions and/or anions, the negative electrode active material is capable of reversibly supporting lithium ions and anions, and the potentials of the positive electrode and the negative electrode are at most 2.0 V after the positive electrode and the negative electrode are short-circuited. The positive electrode and the negative electrode are alternately laminated with a separator interposed therebetween to constitute an electrode unit, the cell is constituted by at least two such electrode units, lithium metal is disposed between the electrode units, and lithium ions are preliminarily supported by the negative electrode and/or the positive electrode by electrochemical contact of the lithium metal with the negative electrode and/or the positive electrode.

It is to provide a lithium ion capacitor having a high energy density, a high output density, a large capacity and high safety. A lithium ion capacitor comprising a positive electrode, a negative electrode and an aprotic organic solvent solution of a lithium salt as an electrolytic solution, wherein a positive electrode active material is a material capable of reversibly supporting lithium ions and anions, a negative electrode active material is a material capable of reversibly supporting lithium ions, and the potentials of the positive electrode and the negative electrode are at most 2.0 V after the positive electrode and the negative electrode are short-circuited, characterized in that the positive electrode and the negative electrode are respectively made by forming electrode layers by the positive electrode active material and the negative electrode active material on both sides of a positive electrode current collector and a negative electrode current collector each having pores penetrating from the front surface to the back surface, the capacitor has such a cell structure that the positive electrode and the negative electrode are wound or laminated, and the outermost portion of the wound or laminated electrodes is the negative electrode.

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Tokyo, Japan

Atsuro Shirakami