A bicyclic triolborate of the general formula

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and its use in an electrolyte composition. The use of a bicyclic triolborate in an electrolyte composition in electrochemical supercapacitors, such as for example in double-layer capacitors in electric motors.

Disclosed are electrolyte compositions for electrochemical devices, where the electrolyte compositions comprise a microemulsion and where the microemulsion comprises an aqueous phase and a water-immiscible phase. Also disclosed are microemulsion electrolyte compositions for electrically rechargeable electrochemical energy storage devices, including ion batteries (such as lithium ion, sodium ion, magnesium ion, calcium ion, and aluminium ion batteries), redox flow batteries and supercapacitors.

Disclosed are electrolyte compositions for electrochemical devices, where the electrolyte compositions comprise a microemulsion and where the microemulsion comprises an aqueous phase and a water-immiscible phase. Also disclosed are microemulsion electrolyte compositions for electrically rechargeable electrochemical energy storage devices, including ion batteries (such as lithium ion, sodium ion, magnesium ion, calcium ion, and aluminium ion batteries), redox flow batteries and supercapacitors.

A nonaqueous electrolyte for an energy storage device according to an aspect of the present invention includes an imide salt (a), a salt (b) in which a charge center element of an anion is boron and which has an oxalato group, and a difluorophosphate (c), in which a content of the imide salt (a) is 3 or more in terms of molar ratio with respect to a total content of the salt (b) in which the charge center element of the anion is boron and which has the oxalato group and the difluorophosphate (c). A nonaqueous electrolyte for an energy storage device according to another embodiment of the present invention includes an imide salt (a), a salt (b) in which a charge center element of an anion is boron and which has an oxalato group, and a difluorophosphate (c), in which a content of the imide salt (a) is 25 mol % or more with respect to a total content of all ionic compounds.

Disclosed are an ultra-low temperature and high-capacity supercapacitor and a preparation method thereof. The electrode material used in the ultra-low temperature and high capacity supercapacitor is a composite porous carbon material comprising micropores and mesopores, the specific surface area of the electrode material is greater than 2500 m.sup.2/g, the pore size of micropores is larger than 0.8 nm, the pore size of mesopores is 2-3.0 nm, and the proportion of micropores is greater than 70%. The electrolyte of the supercapacitor is a solution of spirocyclic quaternary ammonium tetrafluoroborate in a mixed solvent of 1,3-dioxolane (or methyl formate, or a mixture of both)/acetonitrile. Based on the above electrode materials and combined with the above electrolyte, the supercapacitors as prepared can have a mass specific capacitance of greater than 150 F/g and a volume specific capacitance of greater than 80 F/cm.sup.3, under a temperature of −100° C. and at a current density of greater than 1 A/g.

Disclosed are an ultra-low temperature and high-capacity supercapacitor and a preparation method thereof. The electrode material used in the ultra-low temperature and high capacity supercapacitor is a composite porous carbon material comprising micropores and mesopores, the specific surface area of the electrode material is greater than 2500 m.sup.2/g, the pore size of micropores is larger than 0.8 nm, the pore size of mesopores is 2-3.0 nm, and the proportion of micropores is greater than 70%. The electrolyte of the supercapacitor is a solution of spirocyclic quaternary ammonium tetrafluoroborate in a mixed solvent of 1,3-dioxolane (or methyl formate, or a mixture of both)/acetonitrile. Based on the above electrode materials and combined with the above electrolyte, the supercapacitors as prepared can have a mass specific capacitance of greater than 150 F/g and a volume specific capacitance of greater than 80 F/cm.sup.3, under a temperature of −100° C. and at a current density of greater than 1 A/g.

Described herein are liquid, organosilicon compounds that including a substituent that is a cyano (—CN), cyanate (—OCN), isocyanate (—NCO), thiocyanate (—SCN) or isothiocyanate (—NCS). The organosilicon compounds are useful in electrolyte compositions and can be used in any electrochemical device where electrolytes are conventionally used.

Described herein are liquid, organosilicon compounds that including a substituent that is a cyano (—CN), cyanate (—OCN), isocyanate (—NCO), thiocyanate (—SCN) or isothiocyanate (—NCS). The organosilicon compounds are useful in electrolyte compositions and can be used in any electrochemical device where electrolytes are conventionally used.

To provide a power storage device whose charge and discharge characteristics are unlikely to be degraded by heat treatment. To provide a power storage device that is highly safe against heat treatment. The power storage device includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body. The separator is located between the positive electrode and the negative electrode. The separator contains polyphenylene sulfide or solvent-spun regenerated cellulosic fiber. The electrolytic solution contains a solute and two or more kinds of solvents. The solute contains LiBETA. One of the solvents is propylene carbonate.

To provide a power storage device whose charge and discharge characteristics are unlikely to be degraded by heat treatment. To provide a power storage device that is highly safe against heat treatment. The power storage device includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body. The separator is located between the positive electrode and the negative electrode. The separator contains polyphenylene sulfide or solvent-spun regenerated cellulosic fiber. The electrolytic solution contains a solute and two or more kinds of solvents. The solute contains LiBETA. One of the solvents is propylene carbonate.