A process for preparing surface-modified carbon, comprising adding carbon material to a solution of a reaction product of primary aromatic amine and excess molar amount of nitrite source, and recovering surface-modified carbon bearing redox-active sites. Surface-modified carbon material, electrodes and capacitors based thereon are also provided.

A process for preparing surface-modified carbon, comprising adding carbon material to a solution of a reaction product of primary aromatic amine and excess molar amount of nitrite source, and recovering surface-modified carbon bearing redox-active sites. Surface-modified carbon material, electrodes and capacitors based thereon are also provided.

A nonaqueous electrolyte energy storage device according to one aspect of the present invention is a nonaqueous electrolyte energy storage device including: a negative electrode including a negative electrode material layer; and a nonaqueous electrolyte containing an unsaturated cyclic carbonate, in which the negative electrode material layer contains a solid graphite particle with an aspect ratio of 1 or more and 5 or less, and the amount of substance of the unsaturated cyclic carbonate with respect to a surface area of the negative active material layer is 0.03 mmol/m.sup.2 or more and 0.08 mmol/m.sup.2 or less.

Disclosed herein is a method for fabricating an ultracapacitor, the method comprising disposing an energy storage cell comprising energy storage media within a housing; and constructing the ultracapacitor to operate within a temperature range between about 80 degrees Celsius to about 210 degrees Celsius.

Disclosed herein is a method for fabricating an ultracapacitor, the method comprising disposing an energy storage cell comprising energy storage media within a housing; and constructing the ultracapacitor to operate within a temperature range between about 80 degrees Celsius to about 210 degrees Celsius.

An aspect of the present invention is a nonaqueous electrolyte energy storage device including a negative electrode containing metal lithium, a nonaqueous electrolyte including a fluorinated solvent, and a separator with an air permeability resistance of 150 seconds or less.

The present disclosure is directed to a phosphorus-modified ionic liquid compound, the synthesis thereof and an electrochemical cell electrolyte containing the phosphorus-modified ionic liquid compound.

The present disclosure is directed to a phosphorus-modified ionic liquid compound, the synthesis thereof and an electrochemical cell electrolyte containing the phosphorus-modified ionic liquid compound.

An ultracapacitor that includes an energy storage cell immersed in an electrolyte and disposed within an hermetically sealed housing, the cell electrically coupled to a positive contact and a negative contact, wherein the ultracapacitor has a gel or polymer based electrolyte and is configured to output electrical energy at temperatures between about −40° C. and about 250° C. Methods of fabrication and use are provided.

An ultracapacitor that includes an energy storage cell immersed in an electrolyte and disposed within an hermetically sealed housing, the cell electrically coupled to a positive contact and a negative contact, wherein the ultracapacitor has a gel or polymer based electrolyte and is configured to output electrical energy at temperatures between about −40° C. and about 250° C. Methods of fabrication and use are provided.