Nickel composite hydroxide and process for producing same, positive active material for nonaqueous-electrolyte secondary battery and process for producing same, and nonaqueous-electrolyte secondary battery

Abstract

To provide a positive active material which has a moderate particle diameter and has high evenness in particle diameter and a nickel composite hydroxide which is for use as a precursor for the positive active material. When a nickel composite hydroxide is obtained through a crystallization reaction, an aqueous solution for nucleation which contains both a metal compound at least containing nickel and an ammonium ion source is used to conduct nucleation after having been regulated so as to have a pH of 12.0-14.0 at a solution temperature of 25 degree centigrade, and thereafter the resultant aqueous solution, which is for particle growth and which contains formed nuclei, is regulated so as to have a pH that, at a solution temperature of 25 degree centigrade, is 10.5-12.0 and lower than in the nucleation step, thereby growing the particles. This particle growth is conducted in a non-oxidizing atmosphere having an oxygen concentration of 1 vol.% or lower, over a period which ranges from initiation of the particle growth step and which accounts for more than 40% of the whole period of the particle growth step. Furthermore, the stirring power per unit volume in at least the nucleation step is regulated to 0.5-4 kW / m3.

Description

technical field [0001] The present invention relates to a nickel composite hydroxide as a precursor of a positive electrode active material for a non-aqueous electrolyte secondary battery and a method for producing the same, and a positive electrode active material for a secondary battery using the nickel composite hydroxide as a raw material and a method for producing the same , and a nonaqueous electrolyte secondary battery using the positive electrode active material for a nonaqueous electrolyte secondary battery as a positive electrode material. Background technique [0002] In recent years, along with the popularization of portable electronic devices such as mobile phones and notebook personal computers, the development of small and lightweight non-aqueous electrolyte secondary batteries with high energy density has been eagerly expected. In addition, the development of high-output secondary batteries is highly expected as a power source for driving motors, particularly...

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Problems solved by technology

[0022] However, for the positive electrode active material disclosed in Japanese Patent Application Laid-Open No. 2004-253174, since it is a hollow particle, it is expected to increase the specific surface area compared with the solid particle, but there is no description about the particle size.

Therefore, although the improvement of the reactivity with the electrolyte solution due to the increase in the specific surface area is expected, the effect of the micronization on the migration distance of the above-mentioned lithium ions is unclear, and sufficient output characteristics cannot be expected. improve

In addition, its particle size distribution is considered to be equivalent to that of conventional positive electrode active materials. Therefore, there is a high possibility that the selectivity of fine particles will deteriorate due to the unevenness of the applied voltage in the electrode, and the battery capacity will decrease.

[0023] As described above, a lithium composite oxide capable of sufficiently improving the performance of lithium-ion secondary batteries and a composite hydroxide as a raw material for the composite oxide have not been developed at the present stage.

In addition, although various studies have been made on the production method of composite hydroxide, a method capable of producing composite hydroxide as a raw material of composite oxide capable of sufficiently improving the performance of lithium-ion secondary batteries has not been developed on an industrial scale. method

That is, a positive electrode active material with high particle size uniformity and an appropriate particle size, especially a particle size of about 8 to 16 μm, has not been developed, and a positive electrode active material with a large reaction area, such as a hollow structure, has not been developed. , it is necessary to develop this positive electrode active material and its industrial manufacturing method

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