Electrolytes and electrolyte additives for use in energy storage devices, comprising cyclic carbonate compounds.

Electrolytes and electrolyte additives for use in energy storage devices, comprising cyclic carbonate compounds.

An electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z, wherein about 2.2 wt %≤(X+Y)≤about 8 wt %, about 0.1≤(X/Y)≤about 6, 1 wt %≤Y<5 wt %, about 5 wt %≤Z≤about 50 wt %, and about 0.02<(Y/Z)≤about 0.3. The electrolyte further includes at least one selected from the group consisting of a cyclic carbonate ester having a carbon-carbon double bond, a fluorinated chain carbonate ester, a fluorinated cyclic carbonate ester, and a compound having a sulfur-oxygen double bond.

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.

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.

An aspect of the present invention is a nonaqueous electrolyte energy storage device including: a positive electrode including a positive composite layer containing a transition metal oxide and a boron element; a negative electrode; and a nonaqueous electrolyte containing a sulfate compound, in which the content of the boron element in the positive composite layer is 0.03% by mass or more.

An aspect of the present invention is a nonaqueous electrolyte energy storage device including: a positive electrode including a positive composite layer containing a transition metal oxide and a boron element; a negative electrode; and a nonaqueous electrolyte containing a sulfate compound, in which the content of the boron element in the positive composite layer is 0.03% by mass or more.