In some embodiments, an electrode can include a current collector, a composite material in electrical communication with the current collector, and at least one phase configured to adhere the composite material to the current collector. The current collector can include one or more layers of metal, and the composite material can include electrochemically active material. The at least one phase can include a compound of the metal and the electrochemically active material. In some embodiments, a composite material can include electrochemically active material. The composite material can also include at least one phase configured to bind electrochemically active particles of the electrochemically active material together. The at least one phase can include a compound of metal and the electrochemically active material.

In some embodiments, an electrode can include a current collector, a composite material in electrical communication with the current collector, and at least one phase configured to adhere the composite material to the current collector. The current collector can include one or more layers of metal, and the composite material can include electrochemically active material. The at least one phase can include a compound of the metal and the electrochemically active material. In some embodiments, a composite material can include electrochemically active material. The composite material can also include at least one phase configured to bind electrochemically active particles of the electrochemically active material together. The at least one phase can include a compound of metal and the electrochemically active material.

Disclosed are electrolyte compositions comprising aryl group containing certain fluorinated carbonate, and batteries, especially batteries having a high nominal voltage, comprising such electrolyte composition.

Disclosed are electrolyte compositions comprising aryl group containing certain fluorinated carbonate, and batteries, especially batteries having a high nominal voltage, comprising such electrolyte composition.

A lithium ion capacitor has an electrolytic solution that contains: an electrolyte which is a mixture of LiFSI and LiBF.sub.4, where the mol ratio of LiFSI to LiBF.sub.4 is in a range of 90/10 to 30/70; a solvent that contains at least one type of cyclic or chained carbonate compound; and a film-forming agent; wherein the concentration of electrolyte in the electrolytic solution is in a range of 1.2 to 1.8 mol/L. The lithium ion capacitor can maintain its initial high capacitance and low internal resistance, while also undergoing minimal characteristics changes after exposure to a high-temperature, high-voltage environment.

An aspect of the present invention is a nonaqueous electrolyte energy storage device including: a positive electrode including a positive active material layer of 5 mAh/cm.sup.2 or more in capacity density per unit area; a negative electrode including metallic lithium; and a nonaqueous electrolyte including an ionic liquid and a fluorinated ether.

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.)

The present disclosure relates to a novel boron-containing compound and an electrolyte additive for a secondary battery containing the same. An electrolyte for a secondary battery provided in one embodiment contains the novel boron-containing compound, such that decomposition of the electrolyte may be suppressed, thereby improving a capacity and a lifespan of the battery.

The present disclosure relates to the field of energy storage materials, and particularly, to an electrolyte and an electrochemical device. The electrolyte includes an additive A and an additive B, the additive A is selected from a group consisting of multi-cyano six-membered N-heterocyclic compounds represented by Formula I-1, Formula I-2 and Formula I-3, and combinations thereof, and the additive B is at least one halogenated cyclic carbonate compound. The electrochemical device includes the above electrolyte. The electrolyte of the present disclosure can effectively passivate surface activity of the positive electrode material, inhibit oxidation of the electrolyte, and effectively reduce gas production of the battery, while an anode SEI film can be formed to avoid a contact between the anode and the electrode and thus to effectively reduce side reactions.

The present disclosure relates to the field of energy storage materials, and particularly, to an electrolyte and an electrochemical device. The electrolyte includes an additive A and an additive B, the additive A is selected from a group consisting of multi-cyano six-membered N-heterocyclic compounds represented by Formula I-1, Formula I-2 and Formula I-3, and combinations thereof, and the additive B is at least one halogenated cyclic carbonate compound. The electrochemical device includes the above electrolyte. The electrolyte of the present disclosure can effectively passivate surface activity of the positive electrode material, inhibit oxidation of the electrolyte, and effectively reduce gas production of the battery, while an anode SEI film can be formed to avoid a contact between the anode and the electrode and thus to effectively reduce side reactions.