A purpose of the present invention is to provide a lithium ion secondary battery having improved battery characteristics. The lithium ion secondary battery according to the present invention comprises a negative electrode comprising a negative electrode active material comprising a silicon material and an electrolyte solution comprising an electrolyte solvent comprising an open chain sulfone compound, a fluorinated cyclic carbonate and an open chain carbonate and a supporting salt comprising LiN(FSO.sub.2).sub.2.

The present application discloses a lithium ion secondary battery comprising a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film provided on at least one surface of the positive electrode current collector, and the positive electrode film comprises a first positive electrode active material represented by chemical formula Li.sub.1+xNi.sub.aCo.sub.bMe.sub.1-a-bO.sub.2-yA.sub.y and a second positive electrode active material represented by chemical formula Li.sub.1+zMn.sub.cN.sub.2-cO.sub.4-dB.sub.d; the positive electrode plate has a resistivity r of 3500 Ω.Math.m or less; and the electrolyte comprises a fluorine-containing lithium salt type additive. The lithium ion secondary battery provided by the present application is capable of satisfying high safety performance, high-temperature storage performance and cycle performance simultaneously.

The present application discloses a lithium ion secondary battery comprising a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film provided on at least one surface of the positive electrode current collector, and the positive electrode film comprises a first positive electrode active material represented by chemical formula Li.sub.1+xNi.sub.aCo.sub.bMe.sub.1-a-bO.sub.2-yA.sub.y and a second positive electrode active material represented by chemical formula Li.sub.1+zMn.sub.cN.sub.2-cO.sub.4-dB.sub.d; the positive electrode plate has a resistivity r of 3500 Ω.Math.m or less; and the electrolyte comprises a fluorine-containing lithium salt type additive. The lithium ion secondary battery provided by the present application is capable of satisfying high safety performance, high-temperature storage performance and cycle performance simultaneously.

An electrolyte of a lithium-ion secondary battery and an application thereof. The electrolyte of the lithium-ion secondary battery includes an organic solution, a lithium salt, and an additive, and the additive comprises a borate compound. The electrolyte can be better applied to low-cobalt or cobalt-free positive electrode materials, improve the high-temperature cycle and storage performance of the lithium-ion batteries, and inhibit gas generation during high-temperature storage, thereby improving the comprehensive performance of the battery.

An electrolyte of a lithium-ion secondary battery and an application thereof. The electrolyte of the lithium-ion secondary battery includes an organic solution, a lithium salt, and an additive, and the additive comprises a borate compound. The electrolyte can be better applied to low-cobalt or cobalt-free positive electrode materials, improve the high-temperature cycle and storage performance of the lithium-ion batteries, and inhibit gas generation during high-temperature storage, thereby improving the comprehensive performance of the battery.

A lithium secondary battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte. The negative electrode is an electrode in which lithium metal deposits during charging and the lithium metal dissolves during discharging, the separator includes a substrate, a first layer disposed on a first side of the substrate, and a second layer disposed on a second side of the substrate, the first layer includes particles of phosphate containing lithium, the second layer includes a polymer and/or inorganic particles other than the particles of the phosphate, and the polymer is at least one selected from the group consisting of aromatic polyamide, aromatic polyimide, and aromatic polyamide-imide.

Electrolytes and electrochemical cells include a novel ionic liquid having a quaternary cation and a boron cluster anion. In some versions, the boron cluster anion will be a functionalized or unfunctionalized icosahedral boranyl or carboranyl anion. Electrochemical cells have an electrolyte including the ionic liquid. In some versions, the ionic liquid is used as a solvent to dissolve an ionic shuttle salt for transport of active material, with an optional co-solvent. Methods to synthesize the ionic liquid include contacting a boron cluster salt with a quaternary salt to form the ionic liquid by a metathesis reaction.

Electrolytes and electrochemical cells include a novel ionic liquid having a quaternary cation and a boron cluster anion. In some versions, the boron cluster anion will be a functionalized or unfunctionalized icosahedral boranyl or carboranyl anion. Electrochemical cells have an electrolyte including the ionic liquid. In some versions, the ionic liquid is used as a solvent to dissolve an ionic shuttle salt for transport of active material, with an optional co-solvent. Methods to synthesize the ionic liquid include contacting a boron cluster salt with a quaternary salt to form the ionic liquid by a metathesis reaction.

The present invention relates to a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same, the non-aqueous electrolyte comprising a non-aqueous organic solvent, a lithium salt, a first additive including at least one of compounds represented by chemical formulas 1 to 4, and a second additive comprising a cyclic sulfide-based compound, wherein the mixing ratio of the first additive and the second additive is a weight ratio of 0.2:1 to 10:1.

The present invention relates to a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same, the non-aqueous electrolyte comprising a non-aqueous organic solvent, a lithium salt, a first additive including at least one of compounds represented by chemical formulas 1 to 4, and a second additive comprising a cyclic sulfide-based compound, wherein the mixing ratio of the first additive and the second additive is a weight ratio of 0.2:1 to 10:1.