Active substance for nonaqueous electrolyte secondary cell, method for producing active substance, electrode for nonaqueous electrolyte secondary cell, and nonaqueous electrolyte secondary cell

Abstract

To provide an active substance for a nonaqueous electrolyte secondary cell having a large discharge capacity and excellent high discharge performance.Provided is an active substance for a nonaqueous electrolyte secondary cell that contains a lithium transition metal composite oxide that has an alpha-NaFeO2-type crystal structure and is represented by the composition formula Li1+alphaMe1-alphaO2 (where Me is a transition metal element such as Co, Ni, or Mn and alpha is greater than 0), and a method for producing the same. The lithium transition metal composite oxide is characterized by the following: having a molar ratio of Li to a transition metal element Me of 1.2 to 1.4; a D10 of 6 to 9 [mu]m, D50 of 13 to 16 [mu]m, and D90 of 18 to 32 [mu]m where the grain size at which the integrated volume in the grain size distribution of secondary particles is 10%, 50%, and 90% is represented by D10, D50, and D90; and the particle diameter of primary particles is 1 [mu]m or smaller.

Description

Technical field [0001] The present invention relates to an active material for a non-aqueous electrolyte secondary battery, a method for producing the active material, and a non-aqueous electrolyte secondary battery using the active material. Background technique [0002] In the past, LiCoO was mainly used in non-aqueous electrolyte secondary batteries 2 As a positive active material. However, the discharge capacity is about 120 to 130 mAh / g. [0003] As a positive electrode active material material for non-aqueous electrolyte secondary batteries, LiCoO is known 2 Solid solution with other compounds. Has α-NaFeO 2 Type crystal structure, and LiCoO 2 , LiNiO 2 And LiMnO 2 The solid solution of these three components, namely Li[Co 1-2x Ni x Mn x ] O 2 (0<x≤1 / 2) has been published in 2001. LiNi as an example of the above solid solution 1 / 2 Mn 1 / 2 O 2 , LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O 2 It has a discharge capacity of 150-180mAh / g and is also excellent in charge-discharge cycle performanc...

AI Technical Summary

Problems solved by technology

However, there are problems that the initial efficiency at this time is not high enough, and the high-rate discharge performance is poor.

[0026] Patent Documents 2 to 9 describe that the particle size of the lithium-containing transition metal oxide used as the active material is specified, and temporary firing is used when producing the active material. There is no disclosure, and there is also no disclosure that these means are applied to an active material containing a lithium-containing transition metal oxide in which the molar ratio Li / Me of Li to the transition metal element Me containing Co, Ni, and Mn is 1.2 to 1.4.

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