Ultra-thin lithium ion capacitors with ultra-high power performance are provided. Ultra-thin electrodes and ultra-thin lithium films can be used for the ultra-thin lithium ion capacitor. A lithium ion capacitor can include a first positive electrode and a second positive electrode, a negative electrode disposed between the first positive electrode and the second positive electrode, a first lithium film disposed between the first positive electrode and the negative electrode, and a second lithium film disposed between the second positive electrode and the negative electrode. Each of the first and second lithium films can include an electrolyte. In addition, at least one separator can be provided between the first positive electrode and the first lithium film, and at least one separator can be provided between the second positive electrode and the second lithium film.

A composition for an electrochemical device, the composition containing a single-walled carbon nanotube, a binder and a solvent. The binder contains a fluorine-containing copolymer containing a vinylidene fluoride unit and a fluorinated monomer unit other than the vinylidene fluoride unit, and the content of the vinylidene fluoride unit in the fluorine-containing copolymer is 50.0 mol % or more relative to total monomer units. Also disclosed is a positive electrode mixture including the composition and a positive electrode structure including a current collector and the positive electrode mixture layer provided on one or both sides of the current collector.

An electrochemical device, which is a non-aqueous electrochemical device, comprising a polymer (P) enclosed in an inside of the electrochemical device, wherein the polymer (P) is a polymer having a molecular structure containing a unit (P) represented by the following formula (P), the polymer (P) having a weight-average molecular weight of greater than 50,000, as well as an electrode for an electrochemical device, a coating liquid for an electrochemical device, an insulating layer for an electrochemical device, an undercoat layer for an electrochemical device, and an electrolytic solution for an electrochemical device including the polymer (P) and other ingredients:

##STR00001## in the formula (P), R.sup.P is a group of 1 to 20 carbon atoms.

An energy storage device can include a cathode, an anode, and a separator between the cathode and the anode, where the anode and/or electrode includes an electrode film having a super-fibrillized binder material and carbon. The electrode film can have a reduced quantity of the binder material while maintaining desired mechanical and/or electrical properties. A process for fabricating the electrode film may include a fibrillization process using reduced speed and/or increased process pressure such that fibrillization of the binder material can be increased. The electrode film may include an electrical conductivity promoting additive to facilitate decreased equivalent series resistance performance. Increasing fibrillization of the binder material may facilitate formation of thinner electrode films, such as dry electrode films.

An energy storage device can include a cathode, an anode, and a separator between the cathode and the anode, where the anode and/or electrode includes an electrode film having a super-fibrillized binder material and carbon. The electrode film can have a reduced quantity of the binder material while maintaining desired mechanical and/or electrical properties. A process for fabricating the electrode film may include a fibrillization process using reduced speed and/or increased process pressure such that fibrillization of the binder material can be increased. The electrode film may include an electrical conductivity promoting additive to facilitate decreased equivalent series resistance performance. Increasing fibrillization of the binder material may facilitate formation of thinner electrode films, such as dry electrode films.

Provided is a shortened fibrous carbon nanohorn aggregate (CNB) obtained by shortening a CNB having a length of 1 μm or more and a diameter in the short direction in the range of 30 to 100 nm, by oxidizing, stirring in an acid solution, subjecting to an ultrasonic treatment in a liquid, followed by cutting. The shortened CNB has an end surface on which no tip of the plurality of single-walled carbon nanohorns is disposed toward the longitudinal direction at least one end in the longitudinal direction, and has an excellent dispersibility by shortening the length to less than 1 μm.

An alkali metal ion capacitor that is capable of operating in a high-temperature environment at 85° C. The alkali metal ion capacitor is provided with: a positive electrode active material capable of adsorbing and desorbing alkali metal ions; a positive electrode binder for binding the positive electrode active material; a negative electrode active material capable of storing and releasing alkali metal ions; a negative electrode binder for binding the negative electrode active material; and an electrolytic solution that contains an organic solvent and an imide-based alkali metal salt. The negative electrode active material is predoped with alkali metal ions. The positive electrode binder has a Hansen solubility parameter-based RED value of more than 1 with respect to the electrolytic solution.

An alkali metal ion capacitor that is capable of operating in a high-temperature environment at 85° C. The alkali metal ion capacitor is provided with: a positive electrode active material capable of adsorbing and desorbing alkali metal ions; a positive electrode binder for binding the positive electrode active material; a negative electrode active material capable of storing and releasing alkali metal ions; a negative electrode binder for binding the negative electrode active material; and an electrolytic solution that contains an organic solvent and an imide-based alkali metal salt. The negative electrode active material is predoped with alkali metal ions. The positive electrode binder has a Hansen solubility parameter-based RED value of more than 1 with respect to the electrolytic solution.

A process for producing a composite material comprising at least one particulate material and at least one polymeric binder, wherein the at least one particulate material and the at least one polymeric binder are mixed with one another and mechanically processed in the presence of at least one process auxiliary which reduces the mechanical and/or chemical interaction between the surfaces of the at least one particulate material and of the at least one polymeric binder, essentially dispensing with the use of solvents, characterized in that the weight ratio of process auxiliary to polymeric binder is within a range from 3:10 to 0.1:20.

The present invention relates to a three-dimensional structure electrode, a method for manufacturing same, and an electrochemical element including the electrode. The present invention is characterized by comprising: (a) an upper conductive layer and a lower conductive layer which have a structure constituting an assembly within which a conductive material and a porous nonwoven fabric including a plurality of polymeric fibers are three-dimensionally connected in an irregular and continuous manner, thereby forming a mutually connected porous structure; and (b) an active material layer forming the same assembly structure as the conductive layers and forming a three-dimensionally filled structure in which electrode active material particles are uniformly filled inside the mutually connected porous structure formed in the assembly structure, wherein the active material layer is formed between the upper conductive layer and the lower conductive layer.