Disclosed are a hybrid aluminum electrolytic capacitor and a method of producing the same. The preparation method includes impregnating a capacitive element in a fluid to improve the low-temperature property, where the fluid is prepared from a first organic solvent having a boiling point of 180° C. or more and a melting point of −50° C. or less, a small number of an inorganic or organic acid and an amine having a boiling point of 180° C. or more.

A hybrid supercapacitor has two electrodes, one of which functions as a cathode, and the other as an anode. The hybrid supercapacitor further includes an electrolyte arranged between the cathode and the anode. The electrolyte contains a solvent selected from the group consisting of methanol, 1-propanol, 1-heptanol, ethyl acetoacetate, ethylene glycol, diethylene glycol, glycerol, benzyl alcohol, di-n-butyl phthalate and mixtures thereof.

A hybrid supercapacitor has two electrodes, one of which functions as a cathode, and the other as an anode. The hybrid supercapacitor further includes an electrolyte arranged between the cathode and the anode. The electrolyte contains a solvent selected from the group consisting of methanol, 1-propanol, 1-heptanol, ethyl acetoacetate, ethylene glycol, diethylene glycol, glycerol, benzyl alcohol, di-n-butyl phthalate and mixtures thereof.

An anode electrode for an energy storage device includes both an ion intercalation material and a pseudocapacitive material. The ion intercalation material may be a NASICON material, such as NaTi.sub.2(PO.sub.4).sub.3 and the pseudocapacitive material may be an activated carbon material. The energy storage device also includes a cathode, an electrolyte and a separator.

An electrochemical cell has an anode comprising a silicon-based active material, a cathode comprising a cathode active material, and an electrolyte having no ethylene carbonate. The electrolyte comprises a solvent, the solvent being 20 wt % to 50 wt % propylene carbonate with the remainder being a linear solvent, a lithium salt, and less than 15 wt % of one or more additives. The silicon-based anode active material has a specific capacity of ≥700 mAh/g.

The present invention provides an electrolytic solution capable of restraining gas generation. The present invention relates to an electrolytic solution containing a nonaqueous solvent (I), an electrolyte salt (II), and a compound (III) represented by the following formula (1):

##STR00001##

wherein Rf represents a C1-C20 linear or branched fluorinated alkyl group or a C3-C20 fluorinated alkyl group having a cyclic structure, R represents a C1-C20 linear or branched alkylene group or a C3-C20 alkylene group having a cyclic structure, hydrogen atoms in R may be partially or fully replaced by fluorine atoms, Rf and R may each contain an oxygen atom between carbon atoms when having a carbon number of 2 or more as long as oxygen atoms are not adjacent to each other.

The present invention provides an electrolytic solution capable of restraining gas generation. The present invention relates to an electrolytic solution containing a nonaqueous solvent (I), an electrolyte salt (II), and a compound (III) represented by the following formula (1):

##STR00001##

wherein Rf represents a C1-C20 linear or branched fluorinated alkyl group or a C3-C20 fluorinated alkyl group having a cyclic structure, R represents a C1-C20 linear or branched alkylene group or a C3-C20 alkylene group having a cyclic structure, hydrogen atoms in R may be partially or fully replaced by fluorine atoms, Rf and R may each contain an oxygen atom between carbon atoms when having a carbon number of 2 or more as long as oxygen atoms are not adjacent to each other.

Provided are a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the electrolyte salt including at least one first lithium salt selected from LiPF.sub.6, LiBF.sub.4, LiN(SO.sub.2F).sub.2, LiN(SO.sub.2CF.sub.3).sub.2, and LiN(SO.sub.2C.sub.2F.sub.5).sub.2, and at least one second lithium salt selected from a lithium salt having an oxalate structure, a lithium salt having a phosphate structure, and a lithium salt having an S═O group, with a sum total of the first lithium salt and the second lithium salt being four or more, and an energy storage device using the same.

This nonaqueous electrolytic solution is not only able to improve electrochemical characteristics at a high temperature and much more improve a discharge capacity retention rate and low-temperature output characteristics after a high-temperature storage test but also able to improve low-temperature input characteristics even for high-density electrodes.

Provided are a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the electrolyte salt including at least one first lithium salt selected from LiPF.sub.6, LiBF.sub.4, LiN(SO.sub.2F).sub.2, LiN(SO.sub.2CF.sub.3).sub.2, and LiN(SO.sub.2C.sub.2F.sub.5).sub.2, and at least one second lithium salt selected from a lithium salt having an oxalate structure, a lithium salt having a phosphate structure, and a lithium salt having an S═O group, with a sum total of the first lithium salt and the second lithium salt being four or more, and an energy storage device using the same.

This nonaqueous electrolytic solution is not only able to improve electrochemical characteristics at a high temperature and much more improve a discharge capacity retention rate and low-temperature output characteristics after a high-temperature storage test but also able to improve low-temperature input characteristics even for high-density electrodes.

The invention relates to a device of the hybrid supercapacitor type comprising at least one cell comprising: a porous positive electrode comprising activated carbon; a negative electrode comprising a carbonaceous material capable of inserting an alkaline element other than lithium, this carbonaceous material being different from the activated carbon used at the positive electrode; and a non-aqueous electrolyte comprising a salt selected from salts of an alkaline metal other than lithium.