An aspect of the present invention is a nonaqueous electrolyte energy storage device that includes a negative electrode including a lithium alloy and a nonaqueous electrolyte containing a fluorinated solvent, in which the lithium alloy contains silver, and the content of silver with respect to the total content of lithium and silver in the lithium alloy is 3% by mass or more and 20% by mass or less. Another aspect of the present invention is a nonaqueous electrolyte energy storage device that includes a negative electrode including a lithium alloy and a nonaqueous electrolyte including a lithium salt containing fluorine, in which the lithium alloy contains silver, and the content of silver with respect to the total content of lithium and silver in the lithium alloy is 3% by mass or more and 20% by mass or less.

The cathode material contains the active component, the conductive component and the connecting component. Organic biomaterial is used as the active component, acetylene carbon black is used as the conductive component and polyvinylidene fluoride is used as the connecting component.

An electrochemical device includes a positive electrode, a negative electrode, and an electrolyte having lithium ion conductivity. The positive electrode includes a positive current collector and a positive electrode mixture layer supported on the positive current collector. The positive electrode mixture layer contains a positive electrode active material reversibly doped with an anion. The negative electrode includes a negative current collector and a negative electrode mixture layer supported on the negative current collector. The negative electrode mixture layer contains a negative electrode active material reversibly doped with lithium ions. The negative electrode active material contains non-graphitizable carbon. A ratio Mp/Mn of a mass Mp of the positive electrode active material supported on a unit area of the positive electrode to a mass Mn of the negative electrode active material supported on a unit area of the negative electrode is in a range from 1.1 to 2.5, inclusive.

A purpose of the present invention is to provide a method for manufacturing, etc., a member for an electrochemical device in which the problem of irreversible change in the composition of the electrochemical device due to solvent depletion, moisture absorption, etc., during manufacturing of the electrochemical devices is unlikely to occur. This method for manufacturing a member for an electrochemical device includes performing at least one shaping operation described in the present specification on a shaping material composition that comprises: at least one filler (F); a plasticizer (P-S), being water, an ionic liquid, or a mixture thereof; and a polymer (P1), the shaping material composition being substantially free of an organic solvent and having plasticity and self-supporting property.

An electrochemical device includes a positive electrode that includes an active layer containing a polyaniline compound. An infrared absorption spectrum of the active layer has a first peak, a second peak, a third peak, and a fourth peak that are derived from the polyaniline compound. The first peak appears at a wave number in a range from 1,100 cm.sup.−1 to 1,200 cm.sup.−1, inclusive. The second peak appears at a wave number in a range of more than 1,200 cm.sup.−1 and less than or equal to 1,400 cm.sup.−1. The third peak appears at a wave number in a range from 1,450 cm.sup.−1 to 1,550 cm.sup.−1, inclusive. And the fourth peak appears at a wave number in a range of more than 1,550 cm.sup.−1 and less than or equal to 1,650 cm.sup.−1. In a discharged state, a ratio I.sub.D3/I.sub.D0 of a height I.sub.D3 of the third peak to a total I.sub.D0 of heights of the first peak, the second peak, the third peak, and the fourth peak ranges from 0.18 to 1.42, inclusive.

An electrochemical device includes a positive electrode that includes an active layer containing a polyaniline compound. An infrared absorption spectrum of the active layer has a first peak, a second peak, a third peak, and a fourth peak that are derived from the polyaniline compound. The first peak appears at a wave number in a range from 1,100 cm.sup.−1 to 1,200 cm.sup.−1, inclusive. The second peak appears at a wave number in a range of more than 1,200 cm.sup.−1 and less than or equal to 1,400 cm.sup.−1. The third peak appears at a wave number in a range from 1,450 cm.sup.−1 to 1,550 cm.sup.−1, inclusive. And the fourth peak appears at a wave number in a range of more than 1,550 cm.sup.−1 and less than or equal to 1,650 cm.sup.−1. In a discharged state, a ratio I.sub.D3/I.sub.D0 of a height I.sub.D3 of the third peak to a total I.sub.D0 of heights of the first peak, the second peak, the third peak, and the fourth peak ranges from 0.18 to 1.42, inclusive.

A novel electrode is provided. A novel power storage device is provided. A conductor having a sheet-like shape is provided. The conductor has a thickness of greater than or equal to 800 nm and less than or equal to 20 μm. The area of the conductor is greater than or equal to 25 mm.sup.2 and less than or equal to 10 m.sup.2. The conductor includes carbon and oxygen. The conductor includes carbon at a concentration of higher than 80 atomic % and oxygen at a concentration of higher than or equal to 2 atomic % and lower than or equal to 20 atomic %.

A novel electrode is provided. A novel power storage device is provided. A conductor having a sheet-like shape is provided. The conductor has a thickness of greater than or equal to 800 nm and less than or equal to 20 μm. The area of the conductor is greater than or equal to 25 mm.sup.2 and less than or equal to 10 m.sup.2. The conductor includes carbon and oxygen. The conductor includes carbon at a concentration of higher than 80 atomic % and oxygen at a concentration of higher than or equal to 2 atomic % and lower than or equal to 20 atomic %.

An object is to suppress electrochemical decomposition of an electrolyte solution and the like at a negative electrode in a lithium ion battery or a lithium ion capacitor; thus, irreversible capacity is reduced, cycle performance is improved, or operating temperature range is extended. A negative electrode for a power storage device including a negative electrode current collector, a negative electrode active material layer which is over the negative electrode current collector and includes a plurality of particles of a negative electrode active material, and a film covering part of the negative electrode active material. The film has an insulating property and lithium ion conductivity.

An electricity storage device includes a negative electrode having a layered structure that includes an organic backbone layer containing an aromatic compound having an aromatic ring structure, the aromatic compound being in the form of dicarboxylate anions, and an alkali metal element layer containing an alkali metal element coordinated with oxygen in the dicarboxylate anions to form a backbone, a positive electrode that provides electric double-layer capacity, and a nonaqueous electrolyte solution provided between the negative electrode and the positive electrode, the nonaqueous electrolyte solution containing an alkali metal salt. The layered structure may be provided in layers by a π-electron interaction of the aromatic compound and may have a monoclinic crystal structure belonging to the space group P2.sub.1/c. The positive electrode may contain activated carbon having a specific surface area of 1,000 m.sup.2/g or more.