A secondary battery having good performance especially in a high-temperature environment can be obtained by using an electrolyte solution for secondary batteries, which is characterized by containing an ionic liquid represented by formula (1) and a lithium salt.

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(In the formula, each of R.sup.1 and R.sup.2 independently represents an alkyl group having 1-5 carbon atoms; and n represents 1 or 2.)

Disclosed is an aluminum ion capacitor, including a separator, an anode and a cathode, between which the separator is interposed, and an electrolyte contacting the anode and the cathode, wherein the anode contains aluminum, the electrolyte contains aluminum ions, and an electrical double layer is formed at the cathode and intercalation and deintercalation of aluminum ions are performed at the anode. Accordingly, a supercapacitor having increased energy density can be effectively manufactured at lower cost than lithium ion capacitors, and also, the supercapacitor has high material stability and thus is not limited as to electrode configuration, and an electrode configuration that has a low manufacturing cost and is able to increase energy density and power density can be adopted.

Disclosed is an aluminum ion capacitor, including a separator, an anode and a cathode, between which the separator is interposed, and an electrolyte contacting the anode and the cathode, wherein the anode contains aluminum, the electrolyte contains aluminum ions, and an electrical double layer is formed at the cathode and intercalation and deintercalation of aluminum ions are performed at the anode. Accordingly, a supercapacitor having increased energy density can be effectively manufactured at lower cost than lithium ion capacitors, and also, the supercapacitor has high material stability and thus is not limited as to electrode configuration, and an electrode configuration that has a low manufacturing cost and is able to increase energy density and power density can be adopted.

An electrode for an energy storage device is disclosed. The electrode includes an active layer. The active layer includes a network of high aspect ratio carbon elements defining void spaces within the network, a plurality of electrode active material particles disposed in the void spaces within the network, and a polymeric additive, the polymeric additive being at least one of (i) selected from a family of polyamides, or (ii) a modified polyamide or derivative of a polyamide.

An ultracapacitor that contains a first electrode, second electrode, separator, nonaqueous electrolyte, and housing is provided. The first electrode comprises a first current collector electrically coupled to a first carbonaceous coating and the second electrode comprises a second current collector electrically coupled to a second carbonaceous coating. The first current collector and the second current collector each contain a substrate that includes a conductive metal, wherein a plurality of fiber-like whiskers project outwardly from the substrate of the first current collector, the substrate of the second current collector, or both.

An ultracapacitor that contains a first electrode, second electrode, separator, nonaqueous electrolyte, and housing is provided. The first electrode comprises a first current collector electrically coupled to a first carbonaceous coating and the second electrode comprises a second current collector electrically coupled to a second carbonaceous coating. The first current collector and the second current collector each contain a substrate that includes a conductive metal, wherein a plurality of fiber-like whiskers project outwardly from the substrate of the first current collector, the substrate of the second current collector, or both.

Provided herein is an electrochemical cell designed for high current discharge, which includes a cathode strip, an anode strip, and at least two separator strips, being longitudinally stacked to form an electrodes set that is folded into at least four segments and designed to exhibit a ratio of its nominal capacity per its active area lower than 12 mAh/cm.sup.2, such that the cell is characterized by a discharge efficiency at room temperature of at least 30% to a cut-off voltage of ⅔ of its original voltage at a discharge current of 1,250 mA. Also provided are process of manufacturing, and uses of the cell, which is particularly useful in high drain-rate applications as charging a cellular phone.

The present invention provides a thin film forming composition for energy storage device electrodes, said composition containing a conductive carbon material, a dispersant, a solvent and a polymer that has a partial structure represented by formula (P1) in a side chain. ##STR00001##
(In the formula, L represents —O— or —NH—; R represents an alkylene group having from 1 to 20 carbon atoms; T represents a substituted or unsubstituted amino group, a nitrogen-containing heteroaryl group having from 2 to 20 carbon atoms or a nitrogen-containing aliphatic heterocyclic group having from 2 to 20 carbon atoms; and * represents a bonding hand.)

The present invention provides a thin film forming composition for energy storage device electrodes, said composition containing a conductive carbon material, a dispersant, a solvent and a polymer that has a partial structure represented by formula (P1) in a side chain. ##STR00001##
(In the formula, L represents —O— or —NH—; R represents an alkylene group having from 1 to 20 carbon atoms; T represents a substituted or unsubstituted amino group, a nitrogen-containing heteroaryl group having from 2 to 20 carbon atoms or a nitrogen-containing aliphatic heterocyclic group having from 2 to 20 carbon atoms; and * represents a bonding hand.)

Electrode for storing electrical energy including a metal current collector and an active material, the current collector being coated on at least one portion of one of its faces with at least one protective layer placed between the current collector and the active material, the protective layer including: (A) a polymer matrix including: (A1) at least one cross-linked epoxy polymer or copolymer, (A2) at least one elastomer, and (B) conductive fillers. This system is used in aqueous electrolyte supercapacitors, the protective layer allowing a very significant reduction in corrosion problems that are generally associated with the use of aqueous electrolytes to be achieved and the adhesion of the active material to the metal collector to be improved.