Positive electrode active material, production method thereof and non-aqueous electrolyte secondary battery

Abstract

PROBLEM TO BE SOLVED: To enable charging of a positive electrode with an active material at high density, and by generating an intentional voltage level difference at the final stage of discharging by a nonaqueous electrolytic secondary battery, to facilitate monitoring of residual capacity.SOLUTION: A positive electrode active material is obtained by a manufacturing method which includes a step (1) of mixing an Mn with a compound containing at least one substance selected out of a group of substances consisting of an Ni, Cr, Fe, Co and Cu to obtain a material mixture or a step of synthesizing an Mn compound with at least one substance selected from among a group of substances consisting of an Ni, Cr, Fe, Co and Cu to obtain an eutectic compound; a step (2) of mixing the material mixture or the eutectic compound with a lithium compound, a first baking step (3) of heating a mixture obtained at the step (2) to 600°C or higher; and a step of rapidly cooling the positive electrode active material following the first baking step (4).

Description

technical field [0001] The invention relates to a positive electrode active material and a nonaqueous electrolyte secondary battery using the material. Background technique [0002] In recent years, nonaqueous electrolyte secondary batteries used as main power sources of mobile communication devices, portable electronic devices, and the like are characterized by high electromotive force and high energy density. As the positive electrode active material used, for example, lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ) and manganese spinel (LiMn 2 o 4 )Wait. These active materials have a voltage of 4 V or more with respect to lithium. On the other hand, a carbon material is generally used as a negative electrode, and a 4V-class lithium ion battery is constituted by combining this with the above-mentioned positive electrode active material. [0003] For the battery, it is of course required to have a high energy density, and at the same time, it is also requir...

AI Technical Summary

Problems solved by technology

However, the discharge curve of the battery that has been actually used has an S shape and the voltage gradually decreases, or the curve is flat, but the battery voltage suddenly drops at the end of the discharge.

In the former case, although it is not too difficult to monitor the remaining capacity, there is a problem that the voltage should be flat

On the other hand, in the latter case, the voltage change is very small until the discharge is completed, and as a result, it is very difficult to monitor the remaining capacity of the battery

Therefore, making a battery that can properly monitor the remaining capacity becomes another problem

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