Non-aqueous electrolyte secondary battery

Abstract

The nonaqueous electrolyte secondary battery is equipped with a positive electrode containing the lithium transition metal composite oxide having layer structure, a negative electrode containing a negative active material capable of storing or releasing lithium, and a nonaqueous electrolyte having lithium ion conductivity, and boron and at least one kind of group IVa elements are added to the lithium transition metal composite oxide. The objective of the invention is to enhance high-temperature durability (high-temperature storage characteristics) in a nonaqueous electrolyte secondary battery using a lithium transition metal composite oxide having layer structure as a positive active material.

Description

technical field [0001] The present invention relates to nonaqueous electrolyte secondary batteries such as lithium secondary batteries. Background technique [0002] Lithium transition metal composite oxides with layered structure such as lithium cobalt oxide and lithium nickel oxide are used as non-aqueous electrolyte secondary batteries with a positive electrode active material. The voltage is as high as about 4V. In addition, in order to obtain a large capacity, it can be made density battery. However, when these positive electrode active materials are used, if they are left in a high-temperature environment in a charged state, there is a problem that the capacity of the battery decreases. [0003] In order to solve this problem, a technique of substituting the position of the transition metal in the lithium-transition metal composite oxide with a different element, or substituting the position of oxygen with fluorine has been proposed. For example, in order to suppress...

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Problems solved by technology

[0004] However, as mentioned above, when only zirconium is added, sufficient improvement in high-temperature storage characteristics cannot be obtained